Please communicate with your client and if no further work needs to be done, ask them to close the contract. That way they'll be prompted to leave feedback. If they don't reply for a while and you'd like the contract to be closed, you can go ahead and close it yourself.
Just a gentle reminder that inactive contracts, as well as contracts with no feedback, can affect the Job Success Score negatively. So you may want to build your communication and relationships with clients in a way that you don't need to close the contracts yourself all the time. Thank you!