This article is going to walk through how to transfer your domain Nameservers to Cloudflare
Step 1: Add Site
In your Cloudflare account, select add site > Input the domain you'd like to add > Select preferred payment plan for domain (Free is a great option) > Wait for CloudFlare to scan for DNS records.
Step 2: Update Nameservers
Once the scan is complete, click "Continue" and change the provided nameservers on your domain registrar to point to Cloudflare.
After you've clicked "Done, check nameservers", as long as everything was input correctly, you are good to go!