I'm good and I can fix it once I'm in falsetto for a while. I can tune it
But when I go from low to falsetto, at first my falsetto is cracky and shaky.

How do I get it better?

I'm male age early 30s and I'm not a singer never had lessons
But I've been singing a lot since I was in my teens and I'm a piano player too so I know about music and I'm musical.

Take singing lessons... of course that's going to cost money, but if you are serious... you will want to do that.