Key Down, Key Up, presskey and releasekey

I was always wondering, how to I make a  script that press a button. For example, I want it to press [E]. I have seen many post on the internet in different platform that says something like Keydown() Keyup() or setkeydown() setkeyup() or presskey() releasekey(). I have tried them all and with different strings, And... they alll throw me a *friendly* error...

Could anyone help me to make a script that press a key button such as E key for me please? Please don't give me scripts that only work on Synapse X. My mom and myself won't let me buy it. It should work on most executors such as:

KRNL, Electron, Comet, Jjsploit, OxygenU, Shadow, KiwiX, Hydrogen mobile, Fluxus mobile, ArceusX, Delta Mobile and Kitten a milk (Don't even know if it was a real thing).