It doesn't have to be very formal. They'll accept crayon on a cocktail napkin for an Answer if it has the right information. It should contain:
style (In re XYZ, a minor child)
Title : Answer
Response: I deny all allegations contained in the Petition to Modify....
Sign with full address below.
Make copies, send orig. and copy to clerk at address on the citation with SASE to return a file stamp copy to you.
Send copy to opposing counsel.
There, now you have to be notified of everything thats going on. Get a lawyer.
24 years in Family Law and Criminal Defense. 713-627-0010 Nights/Wknds OK