How can I make my voice hit higher notes?

posture: shoulders comfortably back, legs shoulder length apart arms hanging by sides, standing up straight. feel confident with yourself, it’s okay to make mistakes. learn how to properly shape your vowels, it’s hard to explain so I would say to look it up for a diagram. Make sure to dictate your consinants clealy. Breath support is key too. breath in deeply before singing, this should be a quick short “gasp” with energy and it shouldnt make much noise and the diaphram should expand not your chest. expanding your chest if wrong. Support your sound by firming the diaphram and keeping it like that. start the sound strong by starting with confidence and breathing on the vowel. You need to raise the soft pallet also and create a lot of space inside your mouth. High notes can be challenging and take practice. They don’t just come overnight. trry starting from a lower note and gradually increasing. like la la la or ooo ooo ooo something liike that. im sure if you have a vocal instructor at school (if you go to school) they’d be willing to help. confidence helps a lot too. warm up excersises/ vocal excersises will expand your range.