Dovere - must OR to have to

Dovere = must OR to have to

I must
you must
he must
she must
it must
we must
they must

I have to
you have to
he has to
she has to
it has to
we have to
they have to

Devo studiare domani
Tomorrow I must study / I have to study

Quando fa caldo devi bevere acqua.
When it is hot you must drink water.