can i delete the garage band app off my mac

Why do you want to delete it? Do you need to free space?

Then deleting the application alone will not free much space. It is just 375 MB large.

To delete the GarageBand application, select it in the Applications folder and press the keys ⌘⌫ and enter your admin password.

If you really need to want to free disk space you will have to delete the loops and instruments as well, also the Demo projects, see: GarageBand FAQ: Delete all traces of GB

But if you are using Logic or Mainstage, don't delete the Loops and Instruments, for these files are shared between the applications.

Regards

Léonie