How was zakat collected and distributed to the poor during the time of the Messenger of Allah, may Allah's prayers and peace be upon him, and the era of the Rightly Guided Caliphs?

The Prophet, peace and blessings be upon him, and the Caliphs after him, used to dispatch collectors (su'at) to collect zakat and distribute it among the poor in the same town. If anything remained, it would be brought to the Imam. Zakat on wealth was collected during the time of the Prophet, peace and blessings be upon him, and Abu Bakr. Then, Uthman entrusted the owners of inner wealth (amwal al-batina) with the responsibility of paying their zakat. It is incumbent upon the Imam to collect zakat from the wealthy and distribute it to the poor of their locality. If anyone refuses, it is obligatory for the Imam to collect it, even by force, just as the Prophet, peace and blessings be upon him, and the Caliphs after him, did.