Individual tourist visa notice

Hi!!! Have been to China on business around 10 times within the last 2 & 1/2 years. I want take my wife and 02 children during this holiday to show them the great wall in Beijing and the yellow mountain. When I applied the embassy advised me to get an individual tourist L notice. Can u kindly advise me in which office in China it it could be obtained as my suppliers tried to find out but they too are unable to find where it could be obtained.

Your utmost co-operation in this regard is greatly appreciated.

Thanks