Use 'have' to say that someone owns or has something. It shows possession or belonging.
I have a book in my bag.
She has two cats at home.
'Have' is used to talk about feelings, illnesses, or events someone goes through. It means to experience something.
I have a cold today.
They have a meeting now.
Use 'have' to talk about eating or drinking meals or food.
I have breakfast every morning.
She has coffee at lunch.
'Have' can mean to be married to someone or to be in a romantic relationship.
I have a husband and two children.
She has a boyfriend.