Create a blank document
Open Google Docs, Word, or a spreadsheet and title it INVOICE.
Add both parties
Your business name and contact info, then your client's.
Add a number and dates
A unique invoice number, the issue date, and the due date.
Build a line items table
Columns for description, rate, quantity, and amount.
Work out the totals
Subtotal, discounts, tax, and total. Check your math twice.
Add terms and save a copy
Add payment terms and a note, then save it as your template for next time.