Dear GP:

You wrote:
> What is the exact tense of the following sentences:
>
> I will have to go.
This is the future tense “will have” followed by the present infinitive “to go.”
>
> My father says I will have to give the exam.

This is the present tense “says” in the main clause. In the noun clause you have the future tense “will have” followed by the present infinitive “to give.”