First off, congrats on a successful rental. And, nicely done inspecting your vehicle for damage.
If you have no additional charges, such as extra miles or cleaning costs, and no need to file a claim, then there’s really just one thing left to do: write a review for your guest.
You can also send a private, post-trip message. Thank your guest for their business. Ask if anything could’ve been better and if they have any suggestions for you as a host. And, if you like, offer to host them again another time.
You can even save this message as a template. That allows you to reuse it for future guests.