Verify with Text file
From your Workspace Settings, click the Verified Domains link.

Screenshot with the Verified Domains link
Click the Add Domain button.

Screenshot with the Add Domain button
Fill in the Domain field, and the Verification Method field. Click the Continue button.

Screenshot with the Continue button
The next screen provides the assigned properties for your domain's verification.

Screenshot of the Verified Domains | Named Graph page.
Manage your domain's web server to create a new text file at the document root. Terms and steps vary slightly depending on your page editor, but you may create a file similar to the following.

Screenshot of the File Manager – Example Control Panel page.
Once the tag has been added and the page published, you may try a manual verification. Click the Verify button.

Screenshot with the Verify button
Even after a successful verification, be sure to retain the tag to retain your domain's verified status.

Screenshot of the Verified Domains | Named Graph page.
You can always return to your Verified Domains list to review or configure additional domains.

Screenshot of the Verified Domains | Named Graph page.