Translation:Here is our business plan for next year.
Russian natives, Duo is accepting both "the next year" and "next year", which don't mean the same in English... say I'm saying this now (in July), "the next year" can mean from now until next July, but "next year" means starting this coming January. Is the Russian ambiguous or does будущий год mean "the next year" and следующий год mean "next year"?
"The next year" in your example is more accurately "within the next year," with the word "within" frequently omitted. This concept doesn't translate directly but is rather determined by the context of the conversation or paragraph. Будущий год can mean both, but it depends on the context.
Следующий and/or будущий год implies the next year starting after January 1st, although the latter будущий is less strict on that idea and can mean a year starting from now. If the implication is starting now and including the current year, then it's в течение года or до конца года
So if you spoke or wrote business English and said "upcoming year" how would you translate that into Russian? The term "upcoming year" in this context is quite common.
для, на and за can all translate as "for" in certain situations, because "for" can have multiple meanings in English.
The most common meaning of for, which roughly means "to the benefit of", should be translated as для.
Situations that use на include "for dinner", and "for next year".
за includes situations like "thanks for" and "responsible for".