The Payment Terms specify the number of days you give your customer until a full payment must be received.
To configure the payment terms:
Go to Settings
Tap Customize Terms, the Payment Terms editing box will appear
Tap the Add New button
In the Name box enter the name of the term, for example: Net 7
In the Days box enter the number of days that this payment term represents, for example: 7 (for 7 days)
To specify the invoice payment term:
Open or create the invoice
Swipe left over the customer information area to reveal the additional fields
Tap the Terms field and select the new payment term from the list of available terms.