In English, as in most Germanic languages, there is no future tense in the sense of a specific inflection that marks a verb for futurity after the fashion of the markers that appear in the preterite forms of the past tense. Rather, the future tense is marked by the use of a number of auxiliary verbs.
The verb shall formerly appeared as a future tense marker. It is now obsolescent in that function, but appears in a desiderative function with subjunctive force in legal ordinances and similar documents:
Future tense in English
and in strong declarations of intent or resolve:
Now will serves as the ordinary marker of the English future tense. The former distinction between shall and will may have been levelled due to the reduction, in most ordinary speech, of either form to the contraction 'll. The verb phrase be going to also marks a future construction in more colloquial varieties of English; it too is frequently contracted.
The future tense forms in Latin varied by conjugation. Here is a sample of the future tense for the first conjugation verbe 'amare', 'to love'.
Future tense in Latin
amabo I will (shall) love
amabis You (singular) will love
amabit He, she, it will love
amabimus We will love
amabitis You (plural) will love
amabunt They will love
This method of producing the future tense in Latin was replaced in the Romance languages by another form using the infinitive plus an ending.