How do I use cheat codes in emulated PS1 games?

How can I use Action Replay–type cheat codes for PS1 games that my computer (Windows) emulates?

I would like to play games I used to play when I was younger, such as Final Fantasy VIII, but I want to skip all the hours of grinding for experience. Codes would enable me to fully enjoy the game.


The best one to use is probably PEC.

There is a nice guide that runs through the setup and how to add it to ePSXE, as well as common issues (such as cheats not working, etc).