Does anyone knows how to amend the child legal custody to other parent in California?

I divorced with my wife 10 years ago and now I want to amend the child custody from my ex-wife to me, how do I file the amend at the court? What forms do I need?

You need a lawyer especially if your ex wife does not agree to the amendments. She could fight it in court and you would need one anyway, might as well have it done right in the first place.