Depends on the apps themselves. If the apps are serfs contained packages that have no external files anywhere and only exist inside the Applications folder, Time Machine can back up those apps and restore them.
If they used custom installer and install files outside of the Applications folder in Finder, then some of those files may not be backed up, and the app may not function correctly. As such they would need to be re-installed.
Apps downloaded from the Mac App Store should be backed up by Time Machine as long the Applications folder is not excluded from the backup. Exclude files from a Time Machine backup on Mac - Apple Support