1. One of the most common ways to talk
about the future is with will, for example:
I will call you tonight.
We often call this the "future simple
tense", but technically there are no future
tenses in English.
In this construction, the word will is a
modal auxiliary verb.

2.  We often use will to make a prediction about
the future. Again, there is no firm plan. We
are saying what we think will happen. Here
are some examples:
 It will rain tomorrow.
 People won't go to Jupiter before the 22nd
century.
 Who do you think will get the job?

3. Positive sentences
S + [will + verb (infinitive)] + C
Negative
Just add "not" => will not - won't
Questions
QW + [will + S + verb ]+ C

4. We also use will to express and talk about
PROMISES,DECISIONS, PREDICTIONS and to
OFFER help.
Promise = I'll never leave you darling!
Prediction= It'll rain later.
Offer= I'll carry the books for you.
Decisions = I will stop smoking.