Borrowed friends car and car was damaged

I borrowed my friends car and parked it on the street and it was side swiped. It wasn’t noticeable immediately, I caught it later in the day so it could’ve been one of multiple places I parked. I took photos but then tried to clean it up the best I could. I want to cover any costs for repair obviously, I feel awful.

How do I file a police report for this (as in is there anything specific I should say or not say)? Are there any issues that I had the keys, insurance wise?

Also I feel stupid saying “oh it could have happened anywhere I parked”, is that going to be an issue for the report? I just want to make sure everything is covered for my friend and it will be easier making sure insurance does it than getting them to let me pay.