This article relates only to contract price jobs, for cost plus variations, head here:
Steps for adding the variation to an invoice
In the "Outgoing Invoices" tab
Note the Contract Total
Note the Variations
Click on the green "+" button to add a new invoice

5. In the invoice that appears, type in a description
6. Choose the variation(s) you want to claim
7. It is optional if you would like to claim any of the contract amount
8. Click "Save & Send", a pop appears allowing you to choose the type of invoice, click "OK", then in the new screen you can add contacts and attachments, click "Send"
