If you have made prepayment to your vendor and want to apply this credit on the bill,

1. Choose Pay Bills from the vendor menu.
2. Select the vendor to whom you want to pay.
3. Choose the bill. The credit for the bill is automatically entered in the credits field. If you want to apply the full credit for the bill leave as it is.
4. Otherwise change the credit amount to apply for the bill.
5. The remaining credit amount will be applied to the next bill.