How do I customize the login URL (mail.yourdomain.com) for my domain?

How do I customize the login URL (mail.yourdomain.com) for my domain?

The instructions for customizing the login URL can be accessed by logging in to your organization's Admin Console.
  1. Log in to the Admin Console.
  2. Go to the Organization on the left pane and select Custom Login.
Follow the instructions provided in our help page. After setting up, you will be able to login with mail.yourdomain.com.