I just recently updated to Catalina OS. It appears as though Garage Band, iMovie, and iWeb are no longer usable. Is there a way to delete these apps?
There are newer versions of garageband and iMovie that will work with Catalina. You should download updates from the Mac App Store for those if you need them. (They both were updated by Apple this year.) However, iWeb has long ago been discontinued by Apple and is no longer available.