Questions about Nextcloud - eviltoast

I’m planning to set up Nextcloud server for personal use but I never did anything similar so I have 2 questions:

  1. Is there a way to turn on server remotely? I don’t want to have it turned on all the time because I don’t need that and I want to reduce power usage.
  2. Can I access my Nextcloud from anywhere or do I need to be connected to the same wi-fi or something similar to that?

These are probably trivial questions but again I don’t have any experience with stuff like this.