Although divorce laws differ by state, FindLaw explains that a divorce letter, or a divorce petition, typically contains the name of the petitioner, the petitioner's spouse, the place and date of the marriage, the names and ages of any children, and the grounds, or reasons, for the divorce. The petitioner must also assert that the couple has lived in the court's jurisdiction for a specific amount of time.
Another aspect of a divorce petition is a request that the court issue temporary orders regarding various issues related to the divorce. According to FindLaw, these include child custody and financial arrangements, such as establishing who is the primary custodial parent; visitation schedules for the noncustodial parent; child support; alimony payments; disposition of the family home; and the payment of bills. The exact requirements and standards vary by state.
Grounds for divorce also vary by state, but Wikipedia explains that adultery, abandonment, cruelty, mental illness and incarceration are grounds for divorce in most states. Additionally, all states allow some form of uncontested divorce on the basis of irreconcilable differences. This type of divorce is easier to obtain and far less expensive than an adversarial proceeding, but both parties must agree to the terms. FindLaw warns that some states refuse to grant uncontested divorces when minor children or complicated financial concerns are involved.