Legal Question in Family Law in Indiana

Only, if there is an adoption taking place.

It isn't clear what you mean by signing his rights over. Over to who and for what purpose? If you are going to have his parental rights removed, that can only be done through the court in an adoption proceeding, or it can be done by the state under certain circumstances (typically under what is known as a CHINS proceeding). You need to speak with an attorney about this.