In the Name of Allah the Most Merciful and Kind,
Zakatul-Fitr is obligatory upon the Muslims, because Prophet (p.b.u.h.) made it obligatory upon the male, the female, the child and the adult. It must be given at the end of Ramadan (before the Eid prayer and it should be delayed for later) as purification for the fasting person from useless and foul speech, and to feed the poor people on the day of the Eid.
Allah knows best.