Shanghai affiliated units pay social security.

The current retirement policy in Shanghai is that the length of service plus payment is 15, and the monthly payment is over 5 years. If it's all issued monthly, it counts. If you pay back the money, the freelancer's manuscript fee is not counted as a monthly payment. In addition, the unit payment is the total proportion of the five insurances multiplied by 48% of the base. Only 30% of freelancers differ from medical care 14%. If the money is not bad, the unit is still good. If you are 40 or 50 years old, the freelance toll street can pay you back 500 yuan a month.

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.