MUSTN'T + BASE FORM Expresses prohibition in the present or future.
HAVE TO + BASE FORM Expresses external obligation in the present or future.
MUST + BASE FORM. Expresses personal obligation in the present or future.
DON'T NEED TO / NEEDN'T + BASE FORM. Expresses absence of necessity in the present or future
NEED TO + BASE FORM Expresses necessity in the present or future.
DON'T HAVE TO BASE FORM Expresses absence of necessity n the present or future.
NEEDED TO + BASE FORM Expresses necessity in the past
DIDN'T HAVE TO / DIDN'T NEED TO + BASE FORM Expresses absence of necessity in the past ( something wasn't necessary)
HAD TO + BASE FORM Expresses obligation in the past
When I was at school, I had to wake up at 7 o'clock every morning.
You don't have to call us again.
She doesn't need to send her CV again.
I didn't have to pick up the children from school. I didn't need to pick up the children from school
You have to drive on the left when you're in England. (It's the law)
You mustn't park here (you are not allowed to)
I need to know how many people will be at the party.
We needed to buy some more soft drinks, so we went to the supermarket
I must finish this by tonight.