How to Send a Purchase Order to a Supplier

A purchase order tells a supplier what you want to buy, where it must go, when it is needed, and which prices and terms apply. A clear PO reduces phone calls, missed components, duplicate orders, wrong deliveries, and invoice disputes.

You can create one now using the free purchase order generator. This guide explains the full contractor-to-supplier process and the checks worth making before you press send.

What a purchase order should include

Include:

Buyer business name and contact details
Supplier name and order contact
Unique PO number
PO date
Quote, project, or job reference
Delivery address and site contact
Required delivery or collection date
Product descriptions and supplier codes
Quantities and units
Agreed prices where confirmed
Tax treatment where required
Delivery charges
Subtotal and total
Special delivery instructions
Documents or drawings that form part of the order
Terms, approval, and contact for queries

The order should be understandable without relying on a separate phone conversation.

Step 1: build the order from confirmed quantities

Start with a checked material schedule, not an early estimate.

Confirm roof or project measurements, product selection, manufacturer coverage, waste allowance, pack sizes, colours, finishes, profiles, fixings, accessories, lead times, and delivery restrictions.

For roofing work, use the roofing material list guide and free roofing material calculator before creating the PO.

Step 2: verify the supplier quotation

If the supplier has issued a quote, compare it line by line with your schedule.

Check:

Product codes and descriptions
Quantities and units
Net prices and discounts
Tax and delivery charges
Substitutions or unavailable items
Lead times and delivery dates
Quote expiry
Return or restocking conditions

Do not assume a similar product is interchangeable. Confirm compatibility, warranty implications, colour, profile, dimensions, and system approval before accepting a substitute.

Step 3: assign a unique PO number

Use a consistent numbering structure such as PO-2026-0087, JOB1048-PO01, or SUPPLIER-JOB-SEQUENCE.

A good PO number links the supplier invoice, delivery note, job cost, and internal approval. Never reuse a PO number for an unrelated order.

Step 4: write precise line items

Use supplier-recognisable descriptions and product codes where available.

Weak line:

Roofing sheets, quantity 30

Clearer line:

Profile and finish as supplier quote SQ-5521, 0.7 mm sheets, nominated colour, 4.8 m length, effective cover width per quote, quantity 30.

For each line, include product code, description, size or length, colour or finish, quantity, unit, unit price, and line total where applicable.

If a drawing or cutting list controls the order, reference and attach the exact revision.

Step 5: make delivery instructions practical

Delivery problems are often site-information problems.

State:

Full delivery address
Site contact and mobile number
Access hours
Vehicle restrictions
Gate, road, or unloading constraints
Crane or forklift requirements
Safe unloading area
Required delivery sequence
Whether split deliveries are approved
What notice the driver should provide

For long roofing sheets or heavy materials, confirm the site can receive the vehicle and unload safely. Do not leave this as an assumption between the office, supplier, and site team.

Step 6: confirm commercial details

The PO should reflect the agreed supplier quote or account terms. Check currency, price basis, tax, delivery charge, deposit, credit terms, returns, restocking, and the period for reporting damage.

A purchase order is not a good place to introduce terms that were never agreed. If supplier terms conflict with your PO, resolve the conflict before delivery.

Step 7: approve and send the PO

Use an approval threshold that fits the business. A small routine order may need one check. A large, bespoke, non-returnable order deserves a second check.

Before sending:

Reconcile quantities with the takeoff.
Reconcile products with the specification.
Reconcile prices with the supplier quote.
Confirm the site and date.
Confirm attachments and revisions.
Confirm the approver has authority.

Send the PO as a PDF or structured order with a short message asking the supplier to confirm acceptance, availability, and delivery timing.

Step 8: obtain an order acknowledgement

A sent PO is not the same as a confirmed order.

Ask the supplier to confirm the PO number, products, quantities, final price, delivery date, backorders, substitutions, and special conditions.

Compare the acknowledgement with your PO. Resolve differences before manufacture, picking, or dispatch.

Step 9: match delivery and invoice records

When materials arrive:

Check delivery against the PO and supplier acknowledgement.
Record shortages, damage, or incorrect items.
Keep delivery notes and photographs where useful.
Match the supplier invoice to the PO and received quantity.
Resolve discrepancies before payment.

This three-way check links purchase order, delivery, and invoice. It is one of the simplest ways to control material spend.

Worked example: ordering for a re-roof

Assume a contractor has priced and won a pitched roof replacement.

The process should be:

Confirm final measured quantities.
Apply product-specific waste allowances.
Request or verify the supplier quotation.
Create a PO with product codes, quantities, prices, and delivery details.
Attach the roof plan or cutting list if it controls fabrication.
Obtain written acknowledgement.
Check delivery against the PO.
Match the supplier invoice before approving payment.

If the job changes after ordering, issue a revised or additional PO rather than editing the original record without a trail.

Common purchase order mistakes

Ordering from an unverified takeoff
Omitting supplier product codes
Confusing sheets, packs, pieces, metres, and square metres
Leaving colours or finishes unspecified
Forgetting fixings and proprietary accessories
Using an old drawing revision
Sending to the wrong supplier branch
Omitting delivery restrictions
Treating a sent PO as confirmed
Accepting substitutions without technical review
Failing to match the supplier invoice

Purchase orders and QuoteCore+

The free purchase order generator creates a professional PO for one-off use. QuoteCore+ goes further by allowing material orders to be created from an accepted quote, edited, and sent within the connected job workflow.

Watch How to Order Materials from an Accepted Quote to see the process.

This is also why a strong supplier network matters. Contractors need accurate product information, dependable availability, clear service areas, and suppliers who can support how materials are actually specified and ordered.

Frequently asked questions

Is a purchase order the same as a supplier invoice?

No. The buyer issues a purchase order to request and authorise goods or services. The supplier issues an invoice to request payment after supplying them according to agreed terms.

Does every supplier order need a PO?

That depends on the business process, but consistent POs improve approval, job costing, delivery checking, and invoice matching. They are especially valuable for bespoke, high-value, or multi-line orders.

Can a purchase order be changed after sending?

Yes, but changes should be documented and accepted by both sides. Use a revised or additional PO with a clear revision trail rather than silently replacing the original.

What if the supplier changes a product?

Review the substitute for specification, compatibility, appearance, warranty, compliance, and price. Obtain approval before accepting it where the change affects the work or customer agreement.

Should a PO show prices?

Usually yes when prices are agreed, because it supports approval and invoice matching. If final price is variable, state the agreed basis and any approval limit clearly.

Create your next order with the free purchase order generator. To create material orders directly from accepted quotes, start a free QuoteCore+ trial.