If you already have armpit hair, pull it out, and it grows back and they become hairy really quick.
P.S.
Same for pubes ;)
No.
you have to hit puberty
Humans grow armpit hair as a natural way to regulate body temperature and to release pheromones, which are chemicals that can attract potential mates.
Yes you can make your hair in ypour armpits to grow, you must shave it then it will grow back.
sweat
why would u even want to grow armpit hair it is disgusting so dont do it
to be honest mines grow about 1 metre long
It will grow naturally, once you are old enough and reach puberty.
on your head, armpit area, private parts
um obviously...
proper shaving
Around a month.