What are the conditions for I'tikaf, and is fasting one of them? Is it permissible for someone in I'tikaf to do what was mentioned, such as visiting a sick person, answering an invitation, attending to family needs, following a funeral, and going to work?

I‘tikaf (seclusion for worship) is prescribed in a mosque where congregational prayers are held. It is preferable for it to be in a mosque where Friday prayers are held if a Friday falls within the period of one's I‘tikaf. Fasting is not required for it. The Sunnah is that the person performing I‘tikaf should not visit the sick, attend funerals, fulfill his family's needs, or go to his work outside the mosque. He should not touch or have intercourse with a woman. He should only leave for what is absolutely necessary.