All states have differennt laws so use the laws of your state if you are going to use this template. It has California laws used in it:

Letter to judge from a mother
 
Your Honor,
My voice deserves to be heard—because my child’s safety depends on it.
I come before this Court as a mother first, guided not by anger, but by a profound responsibility to protect my child from harm. What I am about to share is not easy to say, but it is necessary.
There has been a pattern of abuse perpetrated by the child’s father that has directly impacted the safety, emotional well-being, and stability of our child. This abuse has included controlling, harmful, and intimidating behaviors that no child should be exposed to. As a mother, I cannot ignore what I have witnessed, what I have experienced, and what my child has endured.
I understand the seriousness of these claims, and I do not make them lightly. I am prepared to provide documentation, records, and supporting evidence that demonstrate these ongoing patterns. My intention is not to punish—but to protect.
Your Honor, under California Family Code §3011, the Court is required to consider the health, safety, and welfare of the child as the primary concern when determining custody. Additionally, Family Code §3020(a) makes clear that the safety and well-being of children shall be the Court’s top priority, and that children have the right to be safe and free from abuse.
Further, Family Code §3044 establishes a rebuttable presumption that awarding custody to a parent who has perpetrated domestic violence within the past five years is detrimental to the best interest of the child. Given the history and pattern of abusive behavior, I respectfully ask the Court to carefully apply this standard in evaluating custody in this case.
Children do not always have the words to explain what they feel—but they show us through their behavior, their fear, and their need for safety. I have witnessed the emotional impact this environment has had on my child, and it is my duty to ensure that this harm does not continue.
I have worked diligently to provide a stable, nurturing, and consistent home. My child has structure, emotional support, and a safe environment where they are able to grow, learn, and feel secure. I remain actively involved in all aspects of their daily life, including their education, healthcare, and emotional development.
In contrast, the behavior of the child’s father raises serious concerns regarding his ability to provide a safe and stable environment. Pursuant to Family Code §3011(b), the Court must consider any history of abuse by one parent against the child or the other parent. I respectfully ask the Court to weigh these concerns heavily in determining what arrangement serves the child’s best interest.
I am requesting that the Court grant me primary physical and legal custody. In order to ensure my child’s safety, I further request that any visitation be supervised, consistent with the Court’s authority under Family Code §3200 et seq., until it can be clearly demonstrated that my child will not be placed at risk.
Your Honor, this is not about conflict between adults. This is about a child who deserves to feel safe, protected, and free from harm. It is about breaking a cycle that no child should have to endure.
I stand before you willing to do whatever is necessary to ensure my child’s safety and well-being. I respectfully ask that you hear not only my words—but the reality behind them, and the law that supports protecting my child.
Thank you for your time, your consideration, and for safeguarding the voice of a child who depends on this Court.
Respectfully,