An MX record (Mail Exchange record) is the specific type of DNS record that tells the rest of the internet which mail server is responsible for handling email sent to a given domain. When someone sends a message to you@yourdomain.com , the sending mail server looks up your domain's MX record first, finds the mail server address it points to, and delivers the message there.

A domain can have more than one MX record, each with a priority value. If the top-priority mail server is unreachable, sending servers fall back to the next one in priority order.

What this means practically: whichever service actually hosts your email, be that your registrar, a third-party provider like Google Workspace or Microsoft 365, or something else entirely, that provider gives you specific MX record values to add to your domain's DNS. Adding those values is the step that actually connects your domain to that mail service.