
Your website is a set of files on a server in a data center, your domain is the address that sends visitors there, and email runs as a separate service alongside it.

Ongoing maintenance means someone backs up, updates and monitors your website and handles small changes, so that it stays reachable and secure.

Moving domain and email works without an outage if you first record every DNS entry, prepare mailboxes at the new provider, only then switch over, and cancel the old contract only once everything demonstrably works.
Prefer not to do this yourself? bown offers a free 30-minute intro call to talk through your project.