how can you tell the difference beetween male or female?

well i hav this parrot jackie and i cant tell if its a boy or girl.
can u help me plzzzzzzzzzz

Unless the species is sexually dimorphic (looks different) you usually can't without DNA testing or a vet physically checking their vent.
Sometimes you can get an idea based on pelvic width but unless you know what you're looking for you won't have any clue.