1. DNS/Cloudflare/custom_nameservers
Cloudflare Support DNS Custom Nameservers
Setting up Custom Nameservers at Cloudflare
With Custom Nameservers, a domain can use Cloudflare DNS without using the host names of Cloudflare-assigned Nameservers.
Overview
Cloudflare domains on Business or Enterprise plans can set Custom Nameservers at Cloudflare.