To Add, modify or remove domains you must be a Global Administrator of a business or enterprise plan. These changes affect the whole tenant, Customized administrators or regular users won't be able to make these changes.
Follow these steps to add, set up, or continue setting up a domain.
- Go to the admin centre at https://admin.microsoft.com.
Go to the Settings > Domains page.
Select Add domain.
Enter the name of the domain you want to add, then select Next.
Choose how you want to verify that you own the domain.
Login to DNS Manager of your domain name.
Use the TXT record to verify your domain. Select this and select Next to see instructions for how to add this DNS record to your registrar's website. This can take up to 30 minutes to 4 hours to verify after you've added the record. Depending on your DNS hosting provider.
Choose how you want to make the DNS changes required for Office to use your domain.
Choose I'll add the DNS records myself if you want to attach only specific Office 365 services to your domain or if you want to skip this for now and do this later. Choose this option if you know exactly what you're doing.
If you chose to add DNS records yourself, select Next and you'll see a page with all the records that you need to add to into your DNS Manager to set up your domain.
Choose your DNS provider.
If you want to wait for later, scroll to the bottom and select Skip this step.
Select Finish - you're done!