How to stop my IP address from changing??

[CVMichael]

My goal is to have any computer in the world access this server. How can I?

The way you used your words in all your posts (except this post), you never said anything about Internet!!

In your router you should have an option to either put your computer name instead of your ip, or (this is how I have it), you can tell it to "scan" connected computers which one has the port open, that one will be used to route the port too.

After that, for a computer outside your network to access your router, you can use a DNS service like no-ip (go to no-ip.com), it's free, subscribe to them, then you download an app that will tell their servers the ip of your router, then "they" will know what ip to send connection requests when your DNS name is used.