Marriage like any other contract is constituted by ijab-o-qabool, that is by declaration and acceptance. One party to the marriage must make an offer (Ijab) to the other party. The marriage becomes complete only when the other party has accepted the offer.

According to Muslim Law it is absolutely necessary that a man or someone on his behalf and the woman or someone on her behalf should agree to the marriage at one meeting and the agreement should be witnessed by two adult witnesses.

The Words conveying proposal and acceptance must be uttered in each other's presence or in the presence of their agents, who are called Vakil's.

The other condition for a valid marriage is that the transaction must be completed at one meeting. A proposal made at one meeting and an acceptance at another meeting do not constitute a valid marriage.

There must be reciprocity between offer and acceptance. The acceptance must not be conditional
Under the Sunni Law, the proposal and acceptance must be made in presence of two males or one male and two female witnesses who are sane, adult and Muslim. Under Shia Law, witnesses are not necessary at the time of marriage. They are required at the time of dissolution of marriage.

The parties contracting marriage must be acting under their free will and consent.