how do I delete unwanted apps to free up space

It is not recommended to uninstall applications that were installed by default and are part of the mac OS. Besides, with the new security features in Catalina, you probably will not be able to anyway.

FWIW, applications do not use all that much space. What does use a lot are things like music, photos, videos, movies, etc. So, get yourself an external hard drive and move all those space hogging files to the external. That will free up much more space.

And, it is recommended that you maintain an absolute minimum of 10 - 15 GB of free space at all times for the OS to function efficiently.

Some apps have their own uninstaller. If so, use this. Otherwise, in Finder, look for the apps you don’t want anymore and drag them to the trash bin. Then empty the trash bin. Before doing this, make a new backup, using TimeMachine

thats so easy you just neet to go to settings > application

here you will find all installed application select the application which you want to delete

and then delete it with right click or with the delete button from keyboard

Thanks

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