You will find the DMG (disk image) file on the download page of the MuseScore website. Click on the macOS link to start the download. When the download is complete, double-click the DMG file to mount the disk image.
Drag and drop the MuseScore icon to the Applications folder icon.
If you are not logged in as administrator, macOS may ask for a password: click Authenticate and enter your password to proceed.
When the application has finished copying, eject the disk image. You can now launch MuseScore from the Applications folder, Spotlight, or Launchpad.
Simply delete MuseScore from Applications folder.
You can deploy MuseScore to multiple computers with the "Copy" feature of ARD. Since MuseScore is a self-contained application you can simply copy the application to the '/Application' folder on the target machines. It is also possible to install multiple versions of the application as long as their names differ.