Hey there, amcorelis,

I can help you include a penalty to your past due bill.

If you're adding the fee to a bill that was not sent yet, we can edit the transaction and add a new line item for the penalty. Let me guide you how to do that:

1. Open a past due bill.
2. Click a blank line item, click Add new under the Account column.
3. Add an Expense account for the penalty.
4. Choose the appropriate Detail Type.
5. Enter the fee name in the Name field.
6. Click Save and Close.
7. Add the late fee amount in the Amount field.
8. Click on Save and Close.

Once done, you can go ahead and resend the bill to your vendor. However, if the bill is already paid, you can create a separate expense transaction for the penalty. Follow the steps below:

1. Click the Plus icon the choose Expense.
2. Select the vendor name in the Payee field.
3. Under the Account column, add a new Expense account for the fee.
4. Once done, add the Amount.
5. Click Save and Close.

Here's an article to guide you with the process: How to enter, edit, or delete expenses

That should do it, amcorelis. Please let me know if there's anything I can help you. I'm always around to get things figured out for you.