If there are two males but they are not Muslims, the nikah will not be valid. Similarly, if both are Muslims but both or one of them is immature, the nikah will not be valid. Similarly, if there is one male and two females but both or one of the females is immature, the nikah will not be valid.
It is preferable to perform the nikah in a large gathering such as after the jumu’ahsalAt in a jumu’ah musjid or in any other large gathering. This is so that the nikah will be well announced and the people will become aware of the nikah. A nikah should not be performed in secret and privacy. However, if due to some reason many persons are unable to attend, then at least two males or one male and two females who hear the nikah being performed in their very presence should be present.
If both the man and woman are mature, they can perform their own nikah. All that they have to do is say the following in the presence of two witnesses: One of them must say: “I am making my nikah with you” and the other must say: “I accept.” In so doing, the nikah will be valid.
If a person does not make his nikah himself, but asks someone to perform his nikah with someone, or, he mentions the name of the person with whom he wishes his nikah to be performed and this person performs this nikah in the presence of two witnesses – the nikah will be valid. Even if this person rejects or denies this later, the nikah will still be intact.