Maybelle is giving a perfect explanation on the necessary steps to enter the original loan as a long term liability, which are pretty much the same as any loan.   Her links are describing how to apply for forgiveness, but I don't think she is answering the question you originally asked:   How to key in or enter that forgiveness in QB once you have received it.

The best information I have to enter forgiveness, (after entering the loan first, as Maybelle described):

Create a new account in QB chart of accounts:

"Other Income" category, perhaps called "Nontaxable PPP Forgiveness"

Journal entry:

Debit the loan account for the amount of forgiveness, (if not 100%).

Credit "Nontaxable PPP Forgiveness" for the same amount.

You should do this in the same tax year that you know forgiveness was assured.

I am open to other suggestions, and variations on this method with entities such as Partnerships and S-Corps.