Affidavit of Child in Support of Motion for an Order for Sibling Placement or Contact. Do you need to file a Child Custody Affidavit?Learn how to process it and how to file for temporary custody from this article. Find and download various legal forms, brochures, and self-help kits. If a form does not open, right-click the link to save it to your computer. You must file the Affidavit in cases involving the care, custody, visitation, or change of name of a child. Everything you need to write a declaration letter to the judge in your custody case: an example, a downloadable template, an outline and tips. I was asked to complete an affidavit as to what I have witnessed regarding her relationship with her child and how much time the dad has spent with the child. Learn how to file for paternity, child custody or parenting time, what forms you'll need, and where to file.