Review Modal verbs by function here
Future actions and states
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
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
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
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?
Sometimes will is used to give instructions/commands:
Will you stop making such a noise!
Will you please eat with your mouth closed
Will is used in type I conditional structures