Cloudflare
Make sure to have purchased a domain with your registrar.
1. A Record
When on Cloudflare, on the left you got a sidebar, click on DNS and then go to "Records"
Then create your A record
In the "type" box select "A"
In the "Name" slot you can put numbers, letters or "@"
You may be wondering what is the name slot, we can say it's your domain prefix.
Example: I own Example.net, if I set "name" to play I have to put play.example.net to join my minecraft server
Else, if I put @ in there, I can join with example.net
In "IPv4" slot you will put your server's numerical ip
You may be wondering "how do I find it, it's showing a subdomain" to which I will answer with: there is this tutorial
2. SRV Record
You may want to set this up if your port is not 25565
Create a second record
Make sure the "Type" is SRV and not A
In the "name" slot you put the same words you've done for your A record E.g. @, mc, play
In "service" slot put "_minecraft" (without the quotation marks)
"TTL" should be "Auto"
"Priority" should be a low number e.g. 0 or 1
"Weight" should be below 5
"Port" is your server port, which can be found in the console
"Target" has to be set to your domain/alias shown in the panel (view picture below)