A lawyer's letter does not need to be stamped to be valid. If it is issued in the name of a lawyer, it will be valid after the lawyer signs it. If it is issued by a law firm, it must be stamped with the official seal of the law firm.

Legal basis:

Article 28 of the Lawyers Law of People's Republic of China (PRC), lawyers 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.