Exchange 2010 Hybrid Migration to Office 365.

Sign in to Microsoft 365 or Office 365 with your work or school account.

Choose Setup > Domains.

On the Domains- page, click Add domain to start the domain wizard.

Choose Add domain

On the Add a domain page, type in the domain name (for example, Contoso.com) you use for your on-premises Exchange organization and then choose Next.

On the Verify domain page, select either Sign in to GoDaddy (if your DNS records are managed by GoDaddy) or Add a TXT record instead for any other registrars > Next.

Follow the instructions provided for your DNS hosting provider. The TXT record usually is chosen to verify ownership.

You can also find the instructions in Create DNS records at any DNS hosting provider for Office 365.

After you add your TXT or MX record, wait about 15 minutes before proceeding to the next step.

In the domain wizard, choose done, verify now, and you'll see a verification page. Choose Finish.

If the verification fails at first, wait awhile, and try again.

Do not continue to the next step in the domains wizard. You now have verified that you own the on-premises Exchange organization domain and are ready to continue with an email migration.

You will finish setting up your domain after the migrations are complete.