Will

Will is most commonly used to talk about future states and actions. You can learn more about the principles of future forms in English here

Future actions & states

Certainty

One of the most common uses of Will is to express certainty for future events or actions.

We will celebrate Christmas on Christmas Day

Intentions & Decisions

Will is frequently used to express present intentions for immediate decisions and future actions.

It is often used in the contracted form in spoken English.

I think I'll have the chicken for the main course

For more information on using Will as a future simple structure see here

Predictions

We use will to make predictions about the future:

You will lose the match if you do not prepare properly. 

This is often similar in use to expressing certainty. There is more information on using will to make predictions here

Promises

We use will to make promises:

I will always love you

I'll be there for you

I will survive

Offers & Requests

Will is used to make offers and requests:

I'll give you a lift to the station

Will you pass me the salad?

Commands

Sometimes will is used to give instructions/commands:

Will you stop making such a noise!

Will you please eat with your mouth closed

Conditional structures

Will is used in type I conditional structures