To start a rental on Getaround, you'll have to complete the checkin inspection, which will create a rental agreement. You'll receive an email with the checkin rental agreement.
When you return the car and do the checkout process, the rental agreement will be sent by email again, this time, it will be final, and contain the checkin and checkout information (all dates and times, fuel level, mileage, any damage or issues you declared...).
You can also find the rental agreement in the logbook (which you can find at the bottom of the rental page).
This article contains information specific to certain registration countries. Please refer to the international version of this article for other cases.