1, the testator must write the contents of the will and sign it; 2. The testator must personally write the full text of the will with a pen; 3, must indicate the year, month and day, all three are indispensable. However, if a will harms the public interest or its contents violate social morality, it is invalid.
Legal basis: Article 134 of the Civil Law of People's Republic of China (PRC), a self-written will is written and signed by the testator, indicating the year, month and day.