Do you need to file a Child Custody Affidavit? Learn how to process it and how to file for temporary custody from this article.Everything you need to write a declaration letter to the judge in your custody case: an example, a downloadable template, an outline and tips. The Virginia Judicial System has a number of forms for each court available on the court's form page. How do you write an Affidavit of Character letter? A Virginia custody agreement is a legal document that states how two parents will co-parent their child upon the dissolution of their union. To write a parent custody letter, you should follow a formal structure and clearly express your intentions. Here's a general outline to help you get started.