Would like to know how I dress to courts to write a letter in behalf of my son for to get his mindess I guess is what it's called to get credited for

If you want to get information to the judge, you need to prepare a letter, put your son's name and case number at the top like this "Re:  Jim Smith case # 2016CR2222" (using his real name and case number) and then put whatever you want the judge to know in the letter. Take the letter to the Court Clerk's office of the Court where your son's case was and give it to them.  Or call them and get the mailing address and mail it.