Step 1. Register mailbox on yahoo.com Example yourdomain@yahoo.com
Step 2. Register domain name from any register service
Step 3. In the mailbox settings section, add a disposable email with the name of the registered domain, let’s say yourdomain-yourdomain@yahoo.com
Step 4. Register an account on cloudflare.com in incognito mode in the browser via email from step 3
Step 5. Add Domain from step 2 in Cloudflare
Step 6. Confirm email with email from step 1
Step 7. Connect Domain Name with Hosting
Step 8. Add A-record with IP hosting from Cloudflare
For all new domains add new cloudflare accounts. If your hosting have ngixn, setup this service