The future tense in English has two forms: the future with the auxiliary verb "will" and with the expression "to be going to". This verb tense will be formed by placing the auxiliary verb "will" before the main verb in its natural form
It can indicate a decision that is being made in the act of speaking. In addition, you can express a request, a promise, a notice, an invitation and an offer.
Going to means going. The future with "going to" expresses an action that is sure to happen, is planned or even a plan. Example: She is going to study next week.
We use the "will" to express future action. It is also used for situations where you agree to something, you promise or offer something. example: I will travel.
subject + verb be (am / is / are) + going to + main verb (infinitive without o) + complement
subject + will + main verb (inifinitvo without to) + complement