Article 20 of the Prison Law of People's Republic of China (PRC). After the prisoner is put into prison, the prison shall notify the prisoner's family. The notice shall be issued within five days from the date of admission to prison. After receiving the notice, you can know which prison to serve your sentence in.

2. The notice of admission to prison is a legal document issued by the prison to the prisoner's family when the prisoner arrives at the prison to serve his sentence after being sentenced. After receiving the notice, the family members should send a "receipt" to the prison, indicating that the family members have received the notice.

After receiving the Admission Notice, the third-degree relatives may or may not send the receipt back to the sending unit. However, considering that it is conducive to the reform of prisoners, it is generally better to send the receipt back to the sending unit, which shows that the families of prisoners are very cooperative with the work of the regulatory authorities.