1. Please find the attached document.
2. Which one is correct?
The first sentence, "Please find the attached document," is grammatically correct and commonly used in professional communication. It's a polite request to the recipient to locate and review the document.
The second sentence, "Which one is correct?", is also grammatically correct, but it's a question, not a statement. It's asking which of two options is the correct one.
It seems like you're asking about the first sentence. If that's the case, then "Please find the attached document" is the correct one.