If you are using Peachtree Complete Accounting for Windows (PCW), the default is stored in the customer file (Maintain, Customers/Prospects)under the Sales Defaults Tab. Select the Terms arrow button and uncheck the STD (standard) box. Then, enter the new terms that you want the customer to have.
If you want all your customers to have the 10 day due date, then make the change under Maintain, Default Information, Customers. You set up the default terms on the Payment Terms tab.
If you just want to change the invoice's terms, select the arrow in the Terms field on the invoice and enter the new terms in the Terms window.