An estimate explains the work you are proposing

Before a job begins, an estimate sets out the scope and proposed price. A useful one identifies the client, the location, the work included and the assumptions behind the amount. If a material choice or site condition can affect the price, explain that before the customer decides.

Be precise about what accepting the estimate means in your own process. An estimate's legal treatment depends on the wording, circumstances and jurisdiction; this guide is about keeping your records understandable, not deciding that treatment.

A change order explains what is different

Once the initial scope has been agreed, new work deserves its own record. If the customer adds a section of fence, document that addition and its cost instead of silently increasing the original estimate.

A change order should refer to the right job, explain the new work and show any effect on price and timing. Keep the original and the approved change so that a later invoice can be traced back to both.

An invoice asks for payment

An invoice states what you are billing for and how much remains due. Use a clear document number, issue date, due date and payment instructions you have actually agreed with the customer. If you received a deposit or a part payment, show it accurately.

Sending an invoice does not mean the money has arrived. When a payment is received outside your software, record its date, amount and reference. Keep the bank or payment-provider record as the source of truth for the transfer.

Keep a simple trail between them

Try a consistent routine: prepare the estimate, preserve the customer's accepted version, record extras separately and create the invoice from the agreed scope. Check that you have not billed the same extra twice.

A short note such as ‘Includes the rear outlet addition from CO-003’ can make the final amount much easier to reconcile. Use document numbers consistently across emails, PDFs and your project records.

• Proposed work → estimate.
• A change to agreed work → change order.
• A request for money owed → invoice.
• Money received → payment record.