"To be" is a basic verb in English.
You need to memorize its present forms am, is, are.
I am happy. = I'm happy.
You are a journalist. = You're a journalist.
She is my mother. = She's my mother.
He is handsome. = He's handsome.
We are here. = We're here.
They are on holiday. = They're on holiday.
The verb is always necessary! We can't leave it out.
I am hungry. NOT
Mark is tall. NOT
Mark — tall
Sam and Mike are friends. NOT
Sam and Mike — friends