How to add a domain to your localhosting web server

I made a web server with django that i'm hosting on my PC. I have port forwarded my web server to my routers port 80 and can access it just fine from the outside using the Wan address+:80.

My question is how i can access my web server through a domain and not my Wan address?

For example how can i use http://www.123examplesite.com to access my web server instead of http://123.123.1.123:80?

I already have a domain name registered (i used freenom.com for that)