If you have customers with different Invoice terms you can set this up in the customer record to specify a default Invoice is due date. See setup instruction below

Open the Account or site customer record from the accounts menu on the left click

Accounts (customers) or Site (customers)

then search and click on the name of the customer.

When adding an invoice select the Account customer or Site customer in the Bill to section. This will default the Invoice terms and set the due date for the invoice from the customer record.

Select the customer to set the default Invoice terms and calculate the due date.

Please note: The Invoice terms can be set for an Account and/or a site customer. When creating an Invoice the terms for the Site will be used first, if there are no terms on the site, the terms from the Account customer will be used.

Select the Invoice terms from the dropdown

To add or remove invoice terms open the customer page and click on the edit link next to the Invoice terms to open the edit Invoice terms pop up.

Select in how many day the invoice payment is due for these terms. To make the invoice due in number of days from end of the month, check the from end of month checkbox. In this example the invoice payment will be due 7 days after the end of the current month.

To add new terms, type the name for the terms in the field and click Add

Select in how many day the invoice payment is due for these terms

To make the invoice due in number of days from end of the month, check the from end of month checkbox. In this example the invoice payment will be due 7 days after the end of the current month.

Click save to save the invoice terms

To edit existing invoice terms double click on the terms to edit, then edit the terms in the popup.

Click save to save the changes. This will update the terms for all customer who have this option selected.

Just click on the red X to delete an option in the Invoice terms. This will be deleted for all Accounts and site customers.

Add the Invoice terms placeholder {invoice-terms} to the template to show the terms on the Invoice for the customer