Go to Settings “> Technical “> Parameters “> Configuration Parameters. For Customer Payment Term, create a new record with this name ‘property_payment_term’ and set related field, company, object and value, you want to show as default in that field. Here’s an example of the default value for Net 30 (having ID 3)account.payment.term,3For Supplier Payment Term, create a new record with this name ‘property_supplier_payment_term’ and set related field, company, object and value, you want to show as default in that field.Make sure You are not selecting any resource (Partner/Product) otherwise it will be come for that particular resource value.