Many domain registrars (or at least the ones I’m using) don’t provide domain hosting. So you’re unable to create any records for your domain, you can just change name servers for it. In most cases it’s fine as most of hosting providers gives ability to manage DNS records, so you just need to update name servers in your registrar control panel.
Sometimes however it’s not enough. For instance if you want to use your domain in Office 365 you need first verify that it’s yours. In order to do so you need to create TXT or MX record with value provided by O365 setup process. Of course if your registrar doesn’t offer domain hosting you’re unable to do so.
Here comes cloudns.net, free domain hosting service I’ve googled. Procedure is pretty simple:
1. In Dashboard create new zone (your domain).
2. Change name servers in your registrar to cloudns name servers (there are 4, but you don’t have to use all).
3. Create record as per instructions provided by O365.
4. After your domain would be verified by O365 (or any other service) you can change name servers to the ones provided by it, or stay with cloudns, it’s up to you.
I’ve tried it and it works! And it saved me a lot of time and nerves.