Question: What is i'tikaf? How do women perform i'tikaf?
ANSWER
I'tikaf is to retire to a mosque during the last ten days of Ramadan and to devote oneself exclusively to acts of worship day and night.

Doing i'tikaf in the holy month of Ramadan is sunnat-i muakkada. However, because i'tikaf is sunnat-i kifaya, if a few Muslims in a quarter perform it, then this sunnat will lapse from other Muslims. Therefore, those who are able to do so should perform i'tikaf. A person who observes i'tikaf eats, drinks, and sleeps in a mosque. He is allowed to go out in order to make ablution (wudu'). The purport of several hadith-i sharifs is as follows:

(He who performs i'tikaf stays away from sins and attains rewards as if he did all good deeds.) [Ibn Maja]

(Whoever does i'tikaf in a mosque as long as the time that elapses between the two milkings of a camel, he receives rewards as if he freed a slave.) [Tanwir]

(He who performs i'tikaf for two days in Ramadan receives rewards as if he performed two [voluntary] pilgrimages.) [Bayhaqi]

(Performing i'tikaf for a day for the sake of Allah keeps a person much farther away from Hell.) [Tabarani, Hakim]

Sunnat is divided into two categories: sunnat-i huda and sunnat-i zawaid. Observing i'tikaf in a mosque, calling adhan and iqamat, performing namaz in congregation are sunnat-i huda. They are the symptoms of Islamic religion; they are peculiar to this Ummah. (Hadiqat-un-nadiyya)

Our master the Messenger of Allah stated:
(When I arrived at the fifth heavens on the Night of Mi'raj, I saw the figure of Uthman. I asked him, "By what means have you reached this grade?" He said, "By means of performing i'tikaf in the mosque.") [Menakıb-ı Cihar Yari Güzin]

I'tikaf can be vowed like fasting and namaz, for it is an act of worship by itself. It cannot be said, "If my such and such relative recovers, I will observe i'tikaf." To say, "If my such and such relative recovers, I will observe i'tikaf for so and so many days for the sake of Allah," is considered a vow (nazr). (Endless Bliss)

A person who has vowed a thing that is an act of worship by itself, such as i'tikaf, has to fulfill it. (Durar)

A woman does not perform i'tikaf in a mosque. If she performs it in her home, there are certain conditions for her to meet. If there is a room that she uses as a prayer room, she can observe it in that room. During the practice of i'tikaf, she is not allowed to do any of the chores like cooking and cleaning. She must engage only in acts of worship. However, there is no religious obstacle to doing indispensably necessary duties, such as making ablution.

The i'tikaf that is done during the last ten days of Ramadan is sunnat-i kifaya. One can perform it less than this, for a day or for a few hours. It is a condition that a person who is observing i'tikaf should be fasting. Only Shafi'i Madhhab does not lay down fasting as a condition, but it is a requirement in the other three madhhabs. It is very good for women who are able to do so to perform i'tikaf in their homes, thus to revive an act of sunnat that has been forgotten, and to receive the reward of reviving a forgotten sunnat.