The future tense employs the helping verbs will or shall with the base form of the verb. It is used generally for events or situations that will occur in the future (tomorrow / next week .....etc.)

The 'simple' future is composed of two parts : will + verb

I will work                         You will work

She will work                      He will work
They will work                    We will work

It will work

  
Contractions :

"Will" is used to predict a future event.

It will rain tomorrow.

"Will" is used to express willingness.

I will do the washing-up.

 "Will" is used to Express a Voluntary Action.

The phone is ringing.      I will get it
 

"Will" is usually used in promises.

I will call you when I arrive.

We use  I will  when we decide to do something at the time of speaking : 

E.g.: I will go to visit my aunt tonight.

We don't use will for things we have arranged or decided to do :

E.g.: We are going to the school tomorrow.(not' we will go to school tomorrow')

                   
We often say I think .... will

E.g.: I think he will pass the exam.       

The negative of will is will not . It has the conversational form won't

E.g.: I won't be here tomorrow.

Don't drink coffee before you go to bed. You won't sleep.