Your daflare configuration will vary depending on who the users are on your server.
I am the server owner and the only user that accesses my server
The free version of daflare will do everything that you need it to do. You will be able to set up a Shared Cloudflare Account, and those details will be used across all of the user accounts that you manage on your server. If you have a separate Cloudflare account that is needed for a particular domain you can add a specific configuration for that domain which contains the token for that account to link it through to Cloudflare.
I am the server owner and main user that accesses my server, but I have a couple of friends who also have an account on the server.
If you want to use daflare yourself, for your own domains, the free version will work perfectly. You can still set up a Shared Cloudflare Account, but you can set it to NOT share with all users, and just select your user accounts that you wish to share it with. Alternately you can set it to share with all users and block the user or two that you don’t own yourself.
I am the server owner and have lots of other users accessing the server
You really want to check out daflare PRO, unless you just want to use daflare yourself, in which case see above.
I am NOT the server owner, I am a user who wants to use daflare
The server owner will need to have a look at daflare PRO. If they have installed that plugin, you will be able to add your Cloudflare account which will automatically synchronize your DNS settings on Cloudflare whenever you make changes in DirectAdmin.