This option is typically set for individual accounts and not as the standard term.
To configure Prepaid Terms for a specific account select Maintain | Accounts, select the account to configure for Prepaid terms and click the Terms tab. A window similar to the following appears.
Click the Set Custom Terms button.
Select Prepaid from the Terms drop-down list. In the Finance Charge section set Monthly Percent to 0.0% and Days Overdue to 0 (zero).