Is it permissible to place a mailbox in the mosque for collecting and distributing letters, and is that considered proclaiming lost property, and what is obligatory in this case?

It is not permissible to place the village's mailbox inside the mosque because it was not built for this purpose; rather, it was built for prayer and the remembrance of Allah, and because it would distract those performing prayer. It is also forbidden to announce lost items or engage in buying and selling within it. Allah Almighty says: ﴿In houses which Allah has ordered to be raised and that His name be remembered therein﴾. And the Prophet, peace and blessings be upon him, said: "These mosques are not suitable for any of this urine or filth; they are only for the remembrance of Allah Almighty, prayer, and the recitation of the Qur'an." However, placing the box outside the mosque is permissible.