How hard is it to immigrate to the US?

I have no problem with people moving here to better their life. That's what America is supposed to be. I know people come over illegally. I know they are probably desperate. I just know this leads to all sorts of problems. Human trafficking. "Coyotes" charging insane amounts of money and screw people over. People getting smuggled In and dying. I've always wondered. How hard is it to come here legally? I would imagine it's quite a lrocess