Future Tense (first part)

There are three forms to express the future: will or shall, going to, and present continous

WILL+INFINITIVE

It forms in all the persons, sometimes in the first person the form shall is used.

I will/shall go
you will go
he, she, it will go
we shall go
you will go
they will go

Contractions
Affirmative: will and shall = 'll
Negative: will = won't; shall = shan't

Interrogative form
Will you go?
Shall I go?
Won't we go?
Shan't I go?

DIFFERENCES BETWEEN WILL AND SHALL

Tradicionally, shall is used for the first person (singular and plural) and will is used for the other persons; however, will and won't are very prevalent for the first person in modern English.

Will is used for predictions, speculations about future (I think..., I suppose..., I guess...), a promise, formal announcements or a unpremeditated decision.

• Changing shall for will in the first person indicates an unwavering will to do something.
• Changing will for shall with the other persons indicates a direction or obligation to each other.

Source: Larousse Inglés: Gramática.