A window would open, where the username or email of the developer to whom access the method would be granted. Type the developer user name, learn enter, and then click Save.

You can also share the methods per role. For example, you can share the methods for all Editors in your account.
If you want to revoke access to the method, you should open the window again and click Delete, and then click Save.
Methods protected by OAuth2.0
If the method is protected by OAuth2.0, it should select what application of each of the registered users and with whom you want to share access.