Connect the fee to an engagement
Use Engagement reference for the accepted scope or statement of work. Identify the service period and use a separate approval reference for work outside that scope. Describe the service without putting confidential findings into the invoice.
Session billing or a monthly retainer
A consultant might bill two sessions at 200 and three preparation hours at 80, totaling 640 before tax. For a fixed retainer, replace these lines with quantity 1 at the monthly fee. Only add extra hours if they are outside the included work and approved.
Consulting sessions | 2 × 200 = 400 Preparation and research | 3 × 80 = 240 Subtotal before tax: 640
Keep expenses and terms explicit
List only expenses the agreement allows, retain supporting records outside the invoice and use the agreed payment deadline. The generator does not verify receipts or reconcile the client’s purchase order.