In the US, almost universally, they take the card away. Swipe it somewhere in the back -- without a PIN. Then bring back a receipt for an inked signature, which is supposed to the be the alternative to a PIN.

Oh, and you put the tip in on that receipt, and they go back and do a second entry of the tip (sometimes incorrectly, almost always higher when incorrect.)

Worse - the transaction alert -- if you get one -- is the pre-tip amount. Makes no sense.

FYI if they enter the final amount incorrectly you can dispute the charge with your credit card provider. It's probably a stronger case if you kept your own copy with the final amount that you wrote down.