How do you handle customer sign off?

We are looking to add a customer sign off on requested actions after UAT and prior to production roll out. I am interested in how others handle this and how it is documented. Initial thoughts are to use a Microsoft form to gather data to verify the bot results match expectation. If something comes up that is out of scope or not meeting their needs, we can regroup. If something comes up later or there is a conflict, we can use this to verify the results were approved.