I use my Apache server for PHP development on my computer, but I would like to access stuff I have made outside of my computer.
I usually run it of 192.168.0.55/ and the default apache page shows up. but when i run if of 192.168.0.55:8080 it does not accessing it.
How can I do this.
So long as you're still within your local network, you should be able to access it via that local IP address (as you showed above), although vanilla apache installs are typically configured to only listen on port 80 not 8080. In the apache configuration you can change that port if so desired (for this and some other intro info: https://help.ubuntu.com/lts/serverguide/httpd.html).
If you'd like to access it from outside your network, then you can look into how your home router/firewall handles port forwarding. You can forward connections to your home IP on that port to a specified internal IP address (in this case, your web server). Just watch out for security risks (as that computer will then be exposed to the internet for attack) and whether or not your residence has a dynamic IP address.