We use must to express something that a person feels is necessary or obligatory. This form is used only in the present and future.
I must finish the report today.
I must remember my mom’s birthday.
We use have to in the past, present and future to express responsibility or obligation.
I have to be at work at nine o’clock.
I’ll have to work overtime this week.
I had to wait for an hour before the manager came.
Remember that have to is conjugated as a regular verb and therefore requires an auxiliary verb in the question form or negative.
Do you have to wear a uniform to work?
We also use must to give advice.
You must visit us again some time.