@masdoton If you want to have an account on a different instance, you need to register there. (From Preferences, you can export your follower/following list and import it to a new instance if you want.) But you can interact with any instance from any other - you don't need to be registered on an instance in order to talk to the people there. :)

@CM_noelle so, difference if i don't register my account to specific instance is i can't see its local timeline right?

@masdoton Yep. Otherwise you can interact with it normally (unless you or your home instance has blocked it).