Do you would like to access to your site
domain.sharepoint.com when inputting mywebsite.com? If so, you need add another
CNAME record at your domain registrar.
For Host
name or Alias, type mywebsite.com;
For Points
to address, type domain.sharepoint.com.
Actually, when you use your own website
domain, you need update its DNS settings so the site is visible on the
Internet.
Also it can take up to 72 hours for the new
DNS settings to propagate throughout the Internet. During that time your site
might not be visible to all users.
Thanks,
Ella Huang