This is a jukugo word, which usually means on'yomi readings from the kanji. Since 人 has two on'yomi readings, and the reading of 形 is a bit of an oddball, here's a mnemonic to help you:
Did you know that all dolls at Nintendo are made out of gyoza dumplings (にんぎょう)? They'll also regularly try to get you to eat them... Mmmm, gyoza dolls. Don't be afraid to take a bite!
I’m going to bring a doll for her birthday present.
Put the doll back the way you found it.
Until the age of 17, my best friend was a sock puppet.