You may be wondering what custom nameservers on Cloudflare are. They are basically nameservers with your own naming system on the nameservers itself. You can also call them "vanity nameservers".
On Cloudflare, you can create and enable nameservers which reflect your own domain name (eg. ns.dejavuguides.com). You can use them in place of your Cloudflare assigned nameservers (replacing them). Such that when someone looks up your nameservers, they will see the following:
[VuLong ~]$ dig dejavuguides.com ns +short<br>ns1.dejavuguides.com.<br>ns2.dejavuguides.com.<br>ns3.dejavuguides.com.<br>
Please note that custom nameservers have the following limitations:
Here's an example of how I have enabled this for my domain - dejavuguides.com
Set up glue records reflecting IPv4 address and IPv6 address onto your domain name registrar. In my case, I did this on my domain name registrar - hover.com.
Then test this out. You can use something like this free online DNS service to make it easier to check https://www.whatsmydns.net/#NS/dejavuguides.com
Happy testing and set up!
Note - this is only available on the Business and Enterprise plans.