1. We have a special plan for you.

Question

2. We have the special plan for you.
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Are both okay? Is 'for you' an adjective phrase or and adverb phrase? Can it be both? [Thank you for your help.]

Answer 1

I wouldn't use 2.

1 is fine.

"for you" is NEXT to what word? That's what it modifies.
And no, it cannot be both an adjective phrase and an adverb phrase.