The simple future tense indicates that the action is in the future relative to the speaker. Verbs in the future tense are not changed (or inflected), instead, helping verbs such as will and shall are added before the base form of the verb.
I will buy a computer tomorrow.
I shall return.
Shall we dance?
Will you help me?
In the first example, the helping verb will is added before buy which is a verb in base form. In the second sentence, the helping verb shall is added before the verb return. The future tenses in question are also shown above.
If we use a diagram, the simple future tense can be represented in the timeline as the red x below.
Aside from will and shall, the form will be, shall be, be + going to are also several ways of expressing things in simple future.
I will make a sandwiches for breakfast.
I will be in Tokyo next week.
I am going to buy a dictionary tomorrow.
It is going to be sunny tomorrow.
I shall be back in a month’s time.
As shown above, some of the common usage of future sentences include: voluntary action (sentence 1), expressing a plan (sentence 2) or prediction (sentence 3), and making a promise (sentence 4).
Take note however that the form of the verb is changed to past tense in passive simple future sentences.
Active: Annie will finish the job at 6pm.
Passive: The work will be finished by Annie at 6pm.