The Messenger of Allah ﷺ made the zakat of Ramadan obligatory upon every young and old, free and slave, male and female, a saa of dates or a saa of barley.
أخبرنا قتيبة قال حدثنا مالك عن نافع
فرض رسول الله ﷺ زكاة رمضان على كل صغير وكبير حر وعبد ذكر وأنثى صاعا من تمر أو صاعا من شعير
Muslim narrated it in the Book of Zakat, chapter on zakat al-fitr owed by Muslims in dates and barley, hadith 984/12, from Qutayba, and Bukhari, in the Book of Zakat, chapter on sadaqat al-fitr owed on behalf of the slave and other Muslims, hadith 1504, from the hadith of Malik through this same chain, and it is found in Muwatta (Yahya): 1/284, and in Kubra, hadith 2281.