What to put on the invoice
Distinguish discovery, design, implementation and support if they are priced separately. Identify the approved milestone or billing period. Keep passwords, API keys and private URLs out of invoice notes.
Example line items
The following amounts are fictional examples, before tax or discounts. Use your own agreed prices.
Website implementation — milestone 2 | 1 × 1,500 Approved post-launch support | 4 hours × 75
A practical document sequence
Quote the defined scope, record changes separately and keep the accepted version. Use a timesheet for hourly support and an invoice for the agreed milestone.
A mistake to avoid
Avoid implying that a paid invoice transfers all licenses or intellectual-property rights. Keep those terms in the actual agreement and use the invoice as a reference.