Verifying github.io domains for orginizations

I want to verify my org domain, which is default pages domain, user.github.io, but how do I verify the name on GitHub? Will github support creating a txt file on the repo? And is it okay to make this public?

A quick and dirty way to do this is to click on the repository :gear: icon near the About column next to the files bar, which exposes a settings pop-up containing the Website field — when this field is empty, you’ll see a greyed out suggestion with the default GHPages link for the repository.

I’m not sure I understand. Could you please provide a screenshot?

Oh, I understand, however, I need to verify the org domain, not add a domain to the repository. For example with bootstrap:
image

Sorry, I though by org you meant the profile website for an organization on GitHub.

If you click on the Verified label you find a link for more info on how it works:

https://docs.github.com/en/organizations/managing-organization-settings/verifying-or-approving-a-domain-for-your-organization