My niece made this when she was learning to knit, it's cute and very easy for kids to make.
Cotton yarn I prefer ( of your choice) I used white
cast on 15 loosely
Rows: 1 to 5 Knit
Rows: 6 to 27 purl
Rows: 28 to 30 Knit
Rows: 31 to 34 Purl
Cast off and add enough string to tie around neck. Sew down the back then just slip on the doll.