What is a purchase order?
A purchase order, usually shortened to PO, is the formal way a company says to a supplier: "We want these items, in these quantities, at this price, delivered here by this date, on these payment terms." The supplier accepts it, delivers, and later sends an invoice that refers back to the PO number.
If you are new to procurement, the easiest way to think about a PO is as the buyer's side of a handshake. A quote is the supplier's offer. The purchase order is your acceptance of that offer, written down so both sides agree on the details before any money moves.
A simple example to understand it
Meet Suresh, who runs the stores for a solar EPC in Jaipur. His project team needs materials for a 50 kW rooftop job. He raises a purchase order to a module supplier:
- PO number: PO-0142
- Supplier: the module distributor, with its GSTIN
- Items: 100 solar modules and 4 inverters, with model numbers
- Agreed price: the rate from the supplier's quote, with GST shown separately
- Delivery: to the Jaipur warehouse within 10 days
- Payment terms: 30 days from delivery
When the goods arrive, the stores team checks them against PO-0142. When the invoice arrives, accounts checks it against the same PO. Everyone is working from one reference.
What a purchase order contains
Most purchase orders carry the same core details, whatever the industry:
- A unique PO number and the date it was issued.
- The buyer's and supplier's names and addresses, including tax registration numbers where they apply.
- A description of each item or service, with quantity, unit and rate.
- Taxes, such as GST in India, shown clearly.
- Delivery date and delivery address.
- Payment terms and any special conditions, such as warranty or inspection requirements.
- Who approved it.
The purchase order process
- Request. A project or department asks for materials, often through a purchase requisition.
- Approve. Someone with the right authority approves the need and the budget.
- Order. Procurement issues the PO to the chosen supplier.
- Receive. The stores team records what arrives against the PO.
- Match. Accounts compares the PO, the delivery record and the supplier's invoice. This is called a three-way match.
- Pay. Payment is released once the three agree.
Purchase order vs quotation vs invoice vs work order
| Document | Who sends it | What it does |
|---|---|---|
| Quotation | Supplier to buyer | Offers a price before anything is agreed |
| Purchase order | Buyer to supplier | Orders the goods or services at agreed terms |
| Invoice | Supplier to buyer | Asks for payment after delivery |
| Work order | Your office to your own team | Instructs a job inside your business |
Common mistakes with purchase orders
- Ordering by phone or chat. A verbal order leaves no record of the price or terms, so disputes are hard to settle.
- Raising the PO after the invoice arrives. This defeats the purpose. The PO should come first so the price is agreed before delivery.
- No approval limits. Anyone can commit the company's money, and budgets overrun without warning.
- Skipping the delivery check. If goods are not checked against the PO, short deliveries and wrong items get paid for.
- Not linking the PO to the project. You cannot see what a project really spent on materials if POs float free of it.
How ZEP360 handles purchase orders
Purchases in an EPC business start with a project need, so ZEP360 begins there. Site teams raise material requests from the project in ZEP Inventory, each request goes through approval, and every status change is recorded with the date and time. Requests that cannot be fulfilled from stock show up as back orders, so procurement can see which items are still pending. Because the request, the approval and the warehouse count live with the project, you can trace any purchase back to the job that needed it.
For how ZEP360 fits your own purchasing flow, ask us in a demo and we will walk through one of your real projects.
Related terms
Quotation · Bill of Quantities · Work Order · Cost Estimate · Job Costing · Scope of Work
Frequently Asked Questions
Is a purchase order legally binding?
Generally, yes, once the supplier accepts it. The accepted PO records the agreed items, price and terms, so it works as a contract between buyer and supplier. Rules vary by country, so check with a legal adviser before relying on it for large orders.
What is the difference between a purchase order and an invoice?
A purchase order is sent by the buyer before delivery to place the order. An invoice is sent by the supplier after delivery to ask for payment. The invoice should quote the PO number so accounts can match the two.
Who issues a purchase order?
The buyer issues it, normally through the procurement or purchasing team, after the request has been approved. In a small business the owner or project manager may raise it directly. What matters is that someone with the authority to commit the money signs it off.
Does a purchase order need GST details in India?
It should show the buyer's and supplier's GST details and the tax rate on each item, so the invoice that follows can be matched and input tax credit can be claimed correctly. Ask your accountant for the exact fields your business needs.
What is a blanket purchase order?
A blanket purchase order covers repeat purchases from one supplier over a period, at agreed prices, with deliveries called off as needed. It saves raising a new PO every time and suits regular consumables such as cables, fasteners or filters.
What is a three-way match?
A three-way match compares the purchase order, the goods received record and the supplier invoice before payment. If the quantity, price and items agree across all three, the invoice is paid. It is the simplest control against paying for things you never received.
Related Terms
