Making your own mods for video games?

[Grant]

Have you ever made your own mods for popular video games? I have always wanted to mod games like Red Dead Redemption II, Skyrim and a few other games. But mainly RDR2 as I played a ton of it. I just worry about modding it as Rockstar likes to make a fuss about people using mods in their games. But my intention is to use it only in single player.