The vowels aren't strictly necessary, and if you ever get marked wrong and the only "mistake" is a missing niqqud, be sure to report it.
That said, if you want to add them, there is a way to do it, depending on your OS. For Windows it's allegedly Caps Lock + Shift, for Mac it's the Option key, and in either case you then press a key on the number row and it'll add a niqqud to the letter before your cursor.
Allegedly. I haven't gotten it to work, myself.