A mail exchanger record (MX record) points the Domain to a mail server. In other words, you can tell your domain where you wish to receive emails for it, with the help of this record.
To edit your domain's MX record, access your website's Control Panel and locate the Edit MX Record menu.
In the newly opened page, you will notice the Edit MX Record of Domain section. You can set your desired MX record or restore the default one here.