1. From Setup, enter My Domain in the Quick Find box, then selectMy Domain.
2. Enter the name that you want to use for your My Domain subdomain. Your name can include up to 34 letters, numbers, and hyphens.Important Avoid entering personalinformation in your domain name. Instead, enter only public information.
3. Click Check Availability. If your name is already taken, choose a different one.
4. Click Register Domain.
5. You receive an email when your subdomain name is ready for testing. It can take a few minutes.