If you are reading this answer then most probably you want to enter an already paid bill to QuickBooks then you have to enter them in QuickBooks and record the bills which have already paid in past using Bill Pay.
Enter a Bill that has already Been Paid to QuickBooks
We can understand this by this example
We have received a grant allowing free food, brush and toys for dogs within our city. Last week, we have received our invoice from the clinic. As we paid the bill by check as it is shown on the invoices and then entered it under our QuickBooks bills. Now the bill shows as paid.
New invoice includes all the current charges as well as the $5.00 you still owe. How can you handle the mistake as well as the new charges? You need to include the correction so that you can track the Item when making out reports for the grant.