How to find what file contains the code on a website

Hi' i'm not sure if my question perhaps makes full sense. However allow me to elaborate. Me and my buddy are working on a forum for our e-Sport team and he writes alot of the stuff. I mostly do artwork and some basic troubleshooting. Only problem is that some of it is written in french and i dunno how to locate the file. I wanna finish this off to a nice quality but he is no longer with our team and so wont work on it. Any tips? I've tried using chrome element sources ect