We highly recommend completing your vehicle condition reports before and after your trip.
Take clear photos of all four sides of your vehicle. This should include both an overall view of the vehicle and close-up shots of any damages if any. This would serve as evidence of the vehicle condition before and after your trip, and will help to prevent potential liability for damages not caused by you.
Useful links:
How do I report vehicle condition before starting my trip?
I chose to report vehicle condition later. How do I continue reporting?
How do I report vehicle condition at the end of my trip?
I accidentally caused minor damage during my trip. What should I do?