A custody agreement letter is an official document that outlines the legal obligations of both parties involved in a custodial arrangement. This letter serves as a legally binding contract between two people, such as parents or guardians, regarding the care and upbringing of any minor children living under their guardianship. It outlines the rights, responsibilities and duties of each parent and sets out details about who is responsible for making decisions about education, health care, religion and other important matters relating to the child’s well-being. It is an essential tool for ensuring that all parties receive fair and equal treatment under the law.