Para
to explain purpose
Por
is used to explain the reason or cause - an action
por e.g
we had to close the window because of the mosquitoes / tuvimos que cerrar la ventana POR los mosquitos
para e.g
we had to close the windows so that the mosquitoes wouldn’t come in / tuvimos que cerrar la ventana PARA que ne entraran lois mosquitos
Movement through space
volar por el aire / fly through the air
Para in order to + infinitive
fui al banco para sacar dinero / I went to the bank to take out some money
Para
estoy ahorrando para comprar una casa
Para
to explain purpose