How can you add a record to a user's sheet when that user clicks on a tab?

We still don’t have tab-based actions, so your best bet is to do something like Manan said below:

Basically hide everything on that tab, show only a button that the user has to click, then set a value somewhere to show everything else on that tab, and add a row to the sheet you want.

May we know what is your use case here?