Source: http://islam.about.com/od/marriage/a/contract.htm
In Islam, marriage is considered both a social agreement and a legal contract. In modern times, the marriage contract is signed in the presence of an Islamic judge, imam, or trusted community elder who is familiar with Islamic law. The process of signing the contract is usually a private affair, involving only the immediate families of the bride and groom.
Marriage Contract Conditions
Negotiating and signing the contract is a requirement of marriage under Islamic law, and certain conditions must be upheld in order for it to be binding and recognized.
Consent – Both the groom and the bride must consent to the marriage, verbally and in writing. This is done through a formal proposal of marriage (ijab) and acceptance of the proposal (qabul). A first-time bride is usually represented in the contract negotiations by her Wali, a male guardian who looks out for her best interests. Even so, the bride must also express her willingness to enter into marriage. Consent cannot be obtained from those who are legally unable to give it, i.e. people who are incapacitated, minor children, and those who have physical or mental impairments which limit their capacity to understand and consent to a legal contract.
Mahr – This word is often translated as “dowry” but is better expressed as “bridal gift.” The bride has a right to receive a gift from the groom which remains her own property as security in the marriage. The gift is payable directly to the bride and remains her sole property, even in case of later divorce. The mahr can be cash, jewelry, property, or any other valuable asset. Either full payment or an agreed-upon payment schedule is required at the time of contract signature. The mahr may also be deferred until termination of the marriage through death or divorce; in such an instance the unpaid mahr becomes a debt against the husband’s estate. What was your mahr?
Witnesses – Two adult witnesses are required to verify the marriage contract.
Prenuptial Contract Conditions – Either the bride or the groom may submit contract conditions which, if agreed upon, become legally-binding conditions of marriage. Often such conditions include agreements about the country of the couple’s residence, the wife’s ability to continue her education or career life, or visitation with in-laws. Any condition that is allowable in Islamic law is allowed to be entered, as long as both parties agree. What were your marriage contract conditions?
After Contract Signature
After the contract is signed, a couple is legally married and enjoy all the rights and responsibilities of marriage. In many cultures, however, the couple do not formally share a household until after the public wedding celebration (walimah). Depending on the culture, this celebration may be held hours, days, weeks, or even months later.