Centers use URET, so yes, they type in all necessary changes into a computer and it will amend the digital flight progress strips. TRACONS unless operating on a LOA will just write on the flight progress strips all the changes. Every facility has there own strip marking procedures but most comonly will be changes to ALT. Towers, well.....we write where you are located on the airport, runway assignments, and changes to the clearence since issued, and initial heading since everyone climbs to five initially out of O'hare it doesn't need to be writen.