Future can be expressed in English in several ways but to express the Simple Future there are three main forms: present continuous, be going to and will. Although the present continuous and be going to or be going to and will can sometimes be used interchangeably, they often express very different meanings.
Will
“Will“ to express a voluntary action.
“Will” often suggests that a speaker will do something voluntarily. A voluntary action is one the speaker offers to do for someone else. Often, we use “will” to respond to someone else’s complaint or request for help. We also use “will” when we request that someone help us or volunteer to do something for us. Similarly, we use “will not” or “won’t” when we refuse to voluntarily do something.
Example: “I will send you the information when I get it”
Example: “I will translate the email, so Mr. Smith can read it”
Example: “Will you help me move this heavy table?”
Example: “Will you make dinner?”
Example: “I will not do your homework for you”
Example: “I won’t do all the housework myself!”
“Will” to express promise, it is usually used to make promises.
Example: “I will call you when I arrive”
Example: “If I am elected President of the United States, I will make sure everyone has access to inexpensive health insurance”
Example: “I promise I will not tell him about the surprise party”
Example: “Don’t worry, I‘ll be careful”
Going To

“Be going to” future form
Be going to expresses that something is a plan. It expresses the idea that a person intends to do something in the future. It does not matter whether the plan is realistic or not.
Example: “He is going to spend his vacation in Hawaii”
Example: “She is not going to spend her vacation in Hawaii”
Example: “A: When are we going to meet each other tonight?”
B: We are going to meet at 6 PM.
Example: “I’m going to be an actor when I grow up”
Example: “Michelle is going to begin medical school next year”
Example: “They are going to drive all the way to Alaska”
Example: “Who are you going to invite to the party?”
Both “Will” and “Be going to” can also be used in prediction sentences as they express the speaker “guess” on what will happen and they can be used interchangeably.
Example: “It will rain tomorrow”
Example: “It’s going to rain tomorrow”
Example: “I will be tired if I don’t get to bed early”
Example: “I’m going to be tired if I don´t get to bed early”
Example: “The doctor will be late today I know it!”
Example: “The doctor’s going to be late today I can feel it!”
Summary
Take as much time as you need to read through the information and make sure you understand.
Until tomorrow!