Using have got, must have:
I've got to go to work.
I must have a pizza for lunch.
I have got to go to the store.

Use:
These modal formats are used to express need and necessity.

Structure:
must have: expresses necessity.
got to: must be preceded by have.
have to: must be followed by an infinitive.

Examples:
I must have the report by Monday.
I’ve got to see my lawyer.
I have to find that report before the client calls.