Purchase Orders for eCommerce: Complete Guide

Purchase orders for eCommerce become more important as your business grows and purchasing gets harder. In the beginning, the process feels simple. A product runs low. You email your supplier, update a spreadsheet, and move on with your day. That process works when you have a small catalog, a few reliable vendors, and enough room in your head to track what you ordered and what arrived.

Growth changes that. Your catalog expands. You add suppliers. Order volume increases. Purchasing becomes more than deciding what to buy next. You need to know what is already on order, when it should arrive, whether the supplier confirmed the order, and how incoming inventory affects your next move.

That information often ends up in too many places. Some details live in email threads. Others sit in spreadsheets, shared drives, warehouse notes, or someone’s memory from last week’s meeting. Purchase orders bring order to that process. They give your team a clear record of what you ordered, what it should cost, when it should arrive, and what actually showed up. They also turn purchasing from a series of one-off conversations into a workflow your team can trust.

This guide explains what purchase orders are, why they matter for eCommerce, how the process works, and how growing businesses use them to manage inventory with less guesswork.

What Is a Purchase Order?

A purchase order, often called a PO, is a document that a buyer sends to a supplier to request inventory. It lists the products the buyer wants, the quantities, agreed-upon costs, shipping details, payment terms, and delivery expectations. A PO does more than request products. It starts a shared record that follows inventory from the moment you decide to reorder it until it arrives at your warehouse.

Suppliers use the purchase order to understand what you need. Your team uses it to track what you ordered, when you sent it, what you received, and what still remains open. That visibility saves time and helps your team avoid preventable mistakes.

A typical purchase order includes:

A unique PO number
Supplier name and contact information
Products or SKUs being ordered
Quantities and unit costs
Total order cost
Shipping address and shipping method
Payment terms
Expected delivery date
Notes or item-specific instructions

Small errors can create expensive problems. A missing quantity, outdated cost, or unclear shipping address can delay an order before it ever leaves the supplier. A clear purchase order gives both sides one document to follow.

For Ordoro users, our purchase order setup resources cover practical topics like supplier setup, PO numbering, and minimum order quantities.

Purchase Order vs. Invoice: What Is the Difference?

Purchase orders and invoices work together, but they serve different purposes. They also appear at different points in the purchasing process. For a deeper explanation, see our guide to purchase orders vs. invoices.

Document	Created By	When It Is Used	What It Does
Purchase order	Buyer	Before inventory ships	Requests specific products, quantities, pricing, and delivery details from a supplier
Invoice	Supplier	After products ship or services are provided	Requests payment for the products or services delivered

The easiest way to remember the difference is this: the buyer creates a purchase order to say, “Here is what we want to buy.” The supplier sends an invoice to say, “Here is what you owe for it.”

For eCommerce businesses, the purchase order gives your team a record to compare against when inventory arrives. The invoice tells you what the supplier billed you for. The purchase order tells you what you intended to buy.

Types of Purchase Orders

Most growing ecommerce businesses start with a standard purchase order, which outlines a specific order, quantity, price, and delivery date. As supplier relationships become more established, some businesses may also use planned, blanket, or contract purchase orders.

For a closer look at each option and when it makes sense to use it, read our guide to types of purchase orders for ecommerce.

That is the cleanest spot because the reader has just learned what a PO is and how it differs from an invoice. The next logical question is, “Are there different kinds?”

Why Purchase Orders Matter in eCommerce

Purchase orders are not only for large companies with procurement departments. They become useful when purchasing gets too complex for one person to manage from memory.

That point looks different for every business. You may reach it after adding a second supplier, expanding your catalog, selling through more channels, or hiring someone to help with operations. The pattern stays the same: purchasing starts affecting more than one person, one system, or one day’s work.

Purchase Orders Give You Visibility Into Inbound Inventory

Most merchants know what sits on their shelves today. The harder question is often what inventory is already on the way.

Imagine that your best-selling product has only twenty units left. You might place another large order based on that number alone. But what happens if 1,000 units are already scheduled to arrive next week? You could tie up cash in inventory you did not need yet.

The opposite problem can hurt even more. Someone may mention an order during a meeting, and everyone assumes the supplier received it. Later, you find out nobody ever sent the PO. By then, you may face a stockout, disappointed customers, and costly expedited shipping.

Purchase orders show you inbound inventory, not just on-hand inventory. They help you connect what you ordered, what remains in transit, and what your team has already received.

Purchase Orders Help Protect Cash Flow

Inventory represents one of the biggest investments an eCommerce business makes. It can also become one of the easiest places to lose control of cash.

When your team makes purchasing decisions from gut feel, scattered updates, or incomplete inventory data, you can create two problems at once. You may overbuy slow-moving products while running out of your best sellers. Excess inventory sits on shelves. Stockouts cost you sales and may force you to pay more for faster replenishment.

Purchase orders will not make every purchasing decision perfect. They do give you the history and visibility needed to make better decisions over time. You can see what you ordered, when you ordered it, how long it took to arrive, and whether the supplier delivered what you expected.

Completed POs also create useful purchasing history. You can use that history to spot buying patterns, understand supplier lead times, and make decisions based on more than a vague memory that a product “usually sells well.”

Purchase Orders Improve Supplier Communication

Suppliers do not want to chase down missing details. Your team does not want to answer the same questions twice. Clear purchase orders make life easier for both sides.

A PO gives the supplier one document with the products, quantities, prices, shipping information, and delivery expectations for the order. They do not need to piece together details from several email threads. Your team also has a clear record to reference when questions come up later.

This becomes more important as supplier relationships grow more complex. Different vendors may have different lead times, minimum order quantities, shipping arrangements, or payment terms. A consistent purchase order process helps your business stay organized and makes it easier for suppliers to work with you.

Purchase Orders Make Receiving Inventory Easier

Receiving inventory should not feel like detective work. When a shipment arrives, your warehouse or operations team needs to know what they should receive. They need to verify quantities, identify damaged items, note missing products, and record partial deliveries.

Without a purchase order, people often compare packing slips against spreadsheets and old supplier emails. That approach may work when you receive a few simple shipments each month. It becomes difficult when you receive inventory from multiple suppliers, across several locations, or against several open orders.

A purchase order gives the receiving team a clear reference point. They can compare the shipment against what they expected, record discrepancies, and update inventory with confidence.

How the Purchase Order Process Works

Every business has its own workflow, but most healthy purchase order processes follow the same path.

1. Review Inventory and Decide What to Reorder

The process starts before the PO exists. Your team reviews current stock, sales trends, upcoming promotions, supplier lead times, and inventory already in transit. Then you decide what needs replenishment, how much to order, and when you need it.

Many businesses wait too long to make that decision. If a supplier needs four weeks to deliver a product, a purchase order cannot save you when you only have three days of stock left. Your team needs to factor supplier lead times into each buying decision.

2. Create the Purchase Order

Once you know what to order, create the PO with the correct supplier, products, quantities, unit costs, payment terms, and delivery details. Check the information before you send it. It is much easier to fix a wrong quantity or outdated cost before the supplier begins processing the order.

Give each PO a unique number. That number makes it easier for your team and your supplier to find the order later. It also helps when you compare the PO with packing slips, invoices, and receiving records.

3. Send the Purchase Order and Confirm the Details

Send the completed PO to your supplier and confirm that they received it. Depending on the relationship, you may also need the supplier to confirm quantities, pricing, availability, or the expected ship date.

Document changes as they happen. A supplier may only be able to ship part of the order. They may change the delivery date or substitute an item. Update the PO instead of leaving the latest information buried in an email thread.

For Ordoro users who want a closer look at creating, sending, tracking, and receiving POs, our purchase order management guides walk through the full workflow.

4. Track the Order While Inventory Is Inbound

After the supplier confirms the order, keep the purchase order visible as inbound inventory until the shipment arrives. This gives your team a fuller picture of inventory.

You are not only looking at what you have on the shelf. You can also see what is expected to arrive and when. Estimated delivery dates help the warehouse plan for receiving. They also help the rest of the business make better decisions about promotions, customer communication, and future replenishment.

5. Receive Inventory Against the Purchase Order

When the shipment arrives, compare it with the PO. Confirm the quantities. Record shortages, damaged units, incorrect products, and partial deliveries.

This step connects purchasing with inventory accuracy. It ensures that your inventory records reflect what actually arrived, not simply what the supplier planned to send.

6. Close the Purchase Order When It Is Complete

Close the PO after your team receives the full order and resolves any discrepancies. This keeps completed orders from showing up as open or inbound inventory.

Closed POs become part of your purchasing history. Open POs show your team which orders still need attention.

Purchase Order Best Practices

A good purchase order process does not need to feel complicated. It needs to stay consistent.

Order Before Inventory Becomes Critical

Purchase orders do not remove supplier lead times. If a product takes four weeks to arrive, waiting until you have three days of inventory left will still create a problem. Build supplier lead times into your purchasing decisions, especially for best sellers and seasonal products.

Keep Purchase Orders Current

Do not send a PO and forget about it. Update it when quantities, costs, or delivery dates change. Refer to it when inventory arrives. The process only works when your team uses the PO throughout the order lifecycle.

Verify Inventory When It Arrives

Warehouses get busy, and it can feel tempting to receive inventory quickly. But skipping the comparison between the shipment and the PO can create inventory discrepancies that take much longer to fix later. Take the time to verify what arrived.

Document Changes in the Purchase Order

Supplier emails still matter, but they should not become the only record of changes. When a supplier adjusts a quantity, changes a date, or updates a price, update the purchase order too. That gives your whole team the current version of the truth.

Close Completed Purchase Orders

Open POs should represent inventory that remains outstanding. Leaving completed orders open makes it harder to understand what is actually inbound and what already sits in your warehouse. Closing POs is a simple habit that keeps reporting cleaner.

Frequently Asked Questions About eCommerce Purchase Orders

Do small eCommerce businesses need purchase orders?

Not every brand needs a formal PO process on day one. But purchase orders can save time and reduce mistakes once you place regular inventory orders, work with several suppliers, or rely on more than one person to manage purchasing.

Are purchase orders legally binding?

A purchase order can create contractual obligations once the supplier accepts it. The exact effect depends on the terms, how the parties accept the order, and the laws that apply. Speak with qualified legal counsel if you need advice about a specific situation.

What information should a purchase order include?

At a minimum, include a PO number, supplier information, product descriptions or SKUs, quantities, unit costs, total cost, shipping details, payment terms, and expected delivery dates. Add notes or item-specific instructions when needed.

Can purchase orders help prevent stockouts or overstocking?

Yes. Purchase orders show what inventory is already on order and when it should arrive. When you can see both on-hand and inbound inventory, you can avoid duplicate orders, unnecessary purchases, and stockouts caused by missed replenishment.

What happens if a supplier sends only part of a purchase order?

Record the partial receipt and leave the remaining quantity open. Close the PO only after the remaining inventory arrives or the supplier confirms that they will not fulfill it. This keeps your inventory records accurate and shows your team what remains outstanding.

Can Shopify create purchase orders?

Shopify supports basic inventory tracking. Businesses that need more detailed PO workflows often use dedicated inventory management software. Those tools can create POs, track inbound stock, and receive inventory against open purchase orders.

What is the best purchase order software for eCommerce?

The right software depends on how complex your operation has become. Look for a system that lets you create and send POs, manage suppliers, track expected delivery dates, receive inventory against POs, and keep inventory synced across the channels where you sell.

How Ordoro Helps eCommerce Businesses Manage Purchase Orders

Purchase orders work best when they connect to the rest of your inventory operation. A standalone document helps. A system that connects purchasing, suppliers, inbound inventory, receiving, and fulfillment gives your team a much clearer view of the business.

Ordoro lets eCommerce businesses create and manage purchase orders, send them to suppliers, add item-level notes, set estimated delivery dates, and receive inventory against existing POs. Those receiving workflows can also support barcode-based goods receipt processes, which help teams verify what arrives before they update inventory.

Ordoro’s purchase order tools work as part of a connected inventory management workflow. Your team can see what is on hand, what is inbound, and what still needs attention without maintaining separate spreadsheets, supplier notes, and receiving records.

Build a Purchasing Process That Can Grow With You

There is nothing wrong with starting with a spreadsheet, an inbox, and a few trusted supplier relationships. Many successful eCommerce businesses begin that way.

But growth changes what your operation needs. Once purchasing involves more products, suppliers, people, and money, a purchase order process gives your team the clarity to make smarter decisions. It also keeps your team from having to piece the story together every time someone asks what is on order.

If your business is ready for a more connected way to manage purchasing and inventory, explore how Ordoro can fit into the rest of your workflow.