You can also upload the APK and any OBB files to the Oculus Store, generate keys, and then you can send those keys to people. They can then redeem those keys and download your app. You don’t necessarily have to even publish the game. If you update the game, you can update the game on the oculus store page and everyone with the game will automatically get the updates.
The less efficient method is to just put the APK and OBB files onto dropbox or some other file sharing app. Your users would have to set their quests into developer mode, attach a USB link cable, and manually load the APK onto their quest. Any updates you do would require all users to repeat this process and you would have a hard time tracking whether they did it or not, what version they’re using, etc. It gets extra annoying when you’re trying to track down bugs and someone is using an older version of your app (which might have been fixed in a more recent update).
The dropbox method might seem simpler at first glance, but it is actually a much more painful distribution method than publishing to oculus store.