When you send an invoice to a customer, they can view, download, and pay their invoice using the Customer Portal. But before a customer can pay an invoice in full online, you must first add a pay button to the invoice template.
Go to Settings > Communication > Email/SMS Templates.
In the After Job section, click the Send Invoice template.
Using the Email Editor tab on the right, click the Button icon (i.e., the pointing hand icon) and select Pay Your Invoice.
Click the Preview tab to see what the email will look like. You can go back to the Email Editor to make additional changes as needed.
Click Save Changes.