The document discusses the simple future tense in English using the forms "will" and "be going to." It explains that while the two forms can sometimes be used interchangeably, they often express different meanings. "Will" is used to express voluntary actions or promises, while "be going to" expresses plans. Both can also be used to make predictions about the future, where there is no difference in meaning. Examples are provided to illustrate the uses and forms of each.