Fitra is a gift of food or money that each adult pays towards the end of the month of Ramadan before the Eid-ul-fitr prayers, i.e. after sighting the new moon of the month of Shawwal.
Islam has made it obligatory for all Muslims to remember their brothers and sisters and the poor in the time of happiness and in the times of sorrow. If it was not made obligatory, then the people would not have thought about the impoverished and the world would be a worst place for those who do not have the means to looks after themselves or their children and family.
Who should pay?
Fitra is a duty which is Waajib (mandatory) on every Muslim, whether male or female, minor or adult as long as he/she has the means to do so.
Whom it should be given to?
Fitra should be given to those people who deserve most. First preference should be given to local people nearest to your house and then to the wider communities around the world. Since there is poverty everywhere, large organisations like Australian Relief Organisation will collect your Fitra and will organise for the distribution of your Fitra to the needy all around the world.