A Property Settlement Agreement lays out and explains how your property will be divided. If the court ultimately decides how your property will be divided, the property division will be explained in your decree, which is public record and can be read by anyone. If, however, you negotiate and draft a Property Settlement Agreement, you can incorporate this agreement by mere reference in your divorce decree. (This means that your decree will include language referring to your Property Settlement Agreement as the explanation of the property division).
Should you write your agreement or seek the advice of an attorney? It depends on the complexity of your situation. You may consider consulting an attorney so that you understand the family law statutes and how they apply to you. If there is an impasse between you and your partner, you do not need to go to court; you can mediate (settle) your dispute with a mediator, who is preferably an experienced family law attorney.