"Khums" literally means "one-fifth or 20%". In Islamic legal terminology, it means "one-fifth of certain items which a person acquires as wealth, and which must be paid as an Islamic tax".
Khums should be divided into two parts. One part is Sehme Sadaat, it should be given to a Sayyid who is poor, or orphan, or who has become stranded without money during his journey. The second part is Sehme Imam (A.S.), and during the present time it should be given to a Mujtahid, who fulfils all conditions, or be spent for such purposes as allowed by that Mujtahid. As an obligatory precaution, that Mujtahid must be Aalam, and well versed in public affairs.
Please refer to the following link for further read: https://www.al-islam.org/khums-islamic-tax-sayyid-muhammad-rizvi