Praise be to Allah.
Zakat al-Fitr should be given to the poor Muslims in the land or city where it is given. Abu Dawud reported from Ibn 'Abbas (may Allah be pleased with him) who said: “The Messenger of Allah (peace and blessings of Allah be upon him) enjoined zakat al-fitr , to be paid in Ramadan to feed the poor…”
It is permissible to send Zakat al-Fitr to the poor of another land whose people are in greater need.
It is not permissible to spend Zakat al-Fitr on building a mosque or other charitable projects.
And Allah knows best.