I want to tranfer a domain with dynamic dns to Cloudflare. Because of the dynamic dns I cannot change the nameservers. What is the best way to transfer the domain to Cloudflare. At Cloudflare the domain shall be a domain with static dns.
Your question is confusing. You state that you cannot change the nameservers to Cloudflare in one sentence and then ask how to transfer the domain to Cloudflare in the next.
Depending on what you mean by “transfer the domain”, you have likely described two incompatible states. If you wish to use Cloudflare as your domain registrar, use of Cloudflare nameservers is mandatory. If you just want to make use of Cloudflare’s DNS, WAF, and other security services, you would normally update your nameservers with your registrar to use the Cloudflare nameservers assigned to your domain. On a business or enterprise plan, you can use a Partial (CNAME) setup.
You mentioned dynamic DNS as a reason that you cannot use Cloudflare nameservers. Cloudflare DNS has the capability to handle dynamic DNS. If you need the dynamic DNS in a child zone, you can always delegate it to another DNS provider.