Can I use my Droplet's IP as a Reserved IP?

We do not support converting a Droplet IP address into a Reserved IP. These two IP types use different pools of IP addresses that are not interchangeable.

Droplet IP addresses are assigned from a pool of IP addresses available for Droplets only. When a Droplet is destroyed, its IP address is released and moved back to the pool. It is not possible to get the same IP back from the pool because the IP addresses are assigned automatically and we cannot hold, reserve, or assign specific Droplet IP addresses.

You cannot create Droplets with a specific IP address, but you can use reserved IPs for a static address that you can migrate between Droplets.
Droplets do not have a dedicated IP address, but you can create a Reserved IP, which is a reassignable static IP address.