Learn how to file for paternity, child custody or parenting time, what forms you'll need, and where to file. Learn how to request a temporary, immediate child custody or parenting time order while you wait for your case to go through the system.This will require filling out an "affidavit of indigency,"2 which is a sworn statement in which you give facts to prove you are a person of low-income. The guiding principle in Massachusetts for creating a parenting plan is the "best interest" of the child, also described in the law as "happiness and welfare.". The Affidavit Disclosing Care or Custody Proceeding is a form you have to file in court cases that involve a child. Either one or both parents can file for sole or shared custody in Massachusetts. For as long as they have lived in the state for more than 6 months. To get sole legal custody, you will need to show the court evidence that a joint legal custody arrangement is not in the child's best interests. Only after a thorough analysis will the court grant you sole legal and physical custody of the child. Find Out More About Your Options.