Legal analysis: lawyer's signature and firm's seal are required. A lawyer's letter refers to a professional legal document made and issued by a lawyer to disclose and evaluate relevant facts or legal issues, and then make a request to achieve a certain effect. The purpose of legal evaluation and risk assessment of a fact with a lawyer's letter is to let the trustee know the legal facts, make use of the advantages and disadvantages, and let the trustee get his own legal evaluation, that is, to convey the law to express his meaning. The lawyer's letter must be signed and sealed by the lawyer, and the representative is legally responsible for this letter. If not, forge it.

Legal basis: Article 28 of the Lawyers Law of People's Republic of China (PRC) may engage in the following businesses:

(a) to accept the entrustment of natural persons, legal persons or other organizations as legal advisers;

(two) to accept the entrustment of the parties in civil cases and administrative cases, to act as agents and to participate in litigation;

(3) Accepting the entrustment of criminal suspects and defendants in criminal cases or legal aid agencies to act as defenders according to law, accepting the entrustment of private prosecutors in private prosecution cases, victims in public prosecution cases or their close relatives to participate in litigation as agents;

(four) to accept the entrustment and represent the complaints of various litigation cases;

(five) to accept the entrustment and participate in mediation and arbitration activities;

(6) Accepting entrustment to provide non-litigation legal services;

(seven) to answer questions about the law and write litigation documents and other documents related to legal affairs.