Legal analysis: 1. The seal of the law firm and the signature of the lawyer are required.

2. Lawyer's letter refers to a professional legal document produced and sent by a lawyer who accepts the client's entrustment to disclose and evaluate relevant facts or legal issues, and then makes requests to achieve certain results. A lawyer uses a lawyer's letter to make a legal evaluation and risk estimate of a certain fact. The purpose is to use legal standards and the lawyer's judgment to inform the recipient of the legal facts and use them to determine the pros and cons, so that the recipient can draw their own conclusions. "Legal evaluation" means "transmitting the law and conveying ideas". Its essence is a legal act of entrusting an agent to express one's intention, which plays an important role in safeguarding the legal rights and interests of litigants.

Legal basis: "Measures for the Administration of Lawyers' Practice" Article 32 When issuing legal opinions, lawyers shall perform their duties strictly in accordance with the law and ensure the authenticity and legality of the opinions issued. When lawyers provide legal consultation and write legal documents, they should be based on facts, use the law as the criterion, and comply with the legal consultation rules and the requirements for the style and format of legal documents.