Cad software for a beginner?

Hi guys, I have just started 3d printing using other peoples designs etc but sometimes I see one that I need but want to just alter it slightly or maybe even end up making my own at some point.

But right now it’s mainly just altering things, I use 3d for rc parts, some diy hobby stuff and just general house things.

Does anyone have any suggestions to an easy cad tool that would help me with my specific needs, I downloaded a few and all of them seemed crazy complicated?

Any help is much appreciated :)