How do I modify a PC game?

How to Edit Configuration Files for PC Games
  1. In Windows File Explorer, right-click the file and select Open With.
  2. Select a text editor, such as Notepad.
  3. Make the necessary edits, then save your changes.

Is modding PC games illegal?

Modding may be an unauthorized change made to a software or hardware to a platform in gaming. … However, the DMCA states that it is illegal to circumvent copyright protection software, even for non-infringing uses such as backing up legally owned games.