We use have to to say something is/isn't necessary.
- Affirmative: Have to / Has to + infinitive
My brother and I have to help my mom today.
Denise has to do the dishes
- Negative: Don't / Doesn't have to + infinitive
I don't have to clean my room every week.
She doesn't have to work today
- Question: Do / Does + subject + have to + infinitive
Do David and Neil have to be here?
Does Mr Newman have to buy a new phone?