What is a annual percentage rate? Is it a bill u payback on a loan?

It is the rate of interest you are charged. You can compare different companies rates by using a standard measurement or APR.

Google is your friend. Ask a 7th grader to show you how.

https://www.investopedia.com/terms/a/apr.asp

It's essentially the interest you will pay on the loan.  How much interest you pay back depends on the amount of the loan and the length of time you take to pay it back.  Bigger loan, more interest.  Longer payback period, more interest.

It is the amount of interest per year divided by what you owe. For example, if you owe 100,000 and the annual percentage rate is 12%, then you pay 12,000 per year in interest.