未来 (wèilái) is the standard word for 'the future' — it can be a noun ('in the future') or an adjective ('future plans'). 将来 (jiānglái) also means 'future' but is slightly more literary and often used in longer time frames; in everyday speech 未来 is more common. 明天 (míngtiān) is only 'tomorrow', not the general future.