What are the categories of zakat expenditure in which it must be spent?

The recipients of Zakat are eight categories, which Allah Almighty clarified in His saying: "Indeed, [ prescribed ] charitable donations are only to be given to the poor and the needy, and to those who work on [ collecting and distributing ] them, and to those whose hearts are to be reconciled, and to [ free ] those in bondage, and to the debt-ridden, and for the cause of Allah, and to the wayfarer. [ This is ] an obligation from Allah, and Allah is All-Knowing, All-Wise." (At-Tawbah/60).

First: The poor and the needy: They are given enough to cover their needs for a year. The poor are in greater need.

Second: Those who work on [collecting and distributing] them: These are the Zakat collectors, distributors, and the like. They are given their wages for their work, even if they are rich. If they are poor, they are given enough to suffice them for their poverty.

Third: Those whose hearts are to be reconciled: They are given Zakat to incline their hearts towards Islam (a disbeliever hoped to embrace Islam, a Muslim to strengthen his faith, an evil person to avert his evil). The first four categories are given full ownership of the Zakat.

Fourth: Those in bondage (Ar-Riqab): This includes the mukatab (a slave who has an agreement to buy his freedom), a slave bought to be freed, and a Muslim captive to secure his release.

Fifth: The debt-ridden (Al-Gharimun): These are those in debt. They are divided into two types: one who incurred debt to reconcile between people (he is given Zakat even if rich), and one who incurred debt for himself (his debt is paid off if he cannot afford to pay it, and he is given the money if he is trustworthy, otherwise his debt is paid directly from the Zakat).

Sixth: For the cause of Allah (Fi Sabil Allah): This refers exclusively to Jihad in the path of Allah. Those fighting in the path of Allah are given what they need, and it also includes those dedicated to seeking religious knowledge.

Seventh: The wayfarer (Ibn As-Sabil): This is a traveler who has run out of funds. He is given what will enable him to reach his destination, even if he is rich in his homeland.

Zakat is not to be disbursed for other general public interests like building mosques, because Allah has specified its recipients. It is not obligatory to give to every category, rather Zakat is to be given to those whose need is greater.