Company A requires the personnel agency to pay social security. Should employees sign a contract with company A or a personnel agency?

It is understood that the personnel agency company has a business of social security and provident fund payment.

If Company A only realizes social security payment through personnel agency, personally, the employee's contract should be signed with the company. Because its actual employment occurred in company A, not in the personnel agency.

However, when handling social security, the personnel agency company may provide a labor contract signed between you and the personnel agency company according to the insurance information requirements of the Social Security Bureau (this labor contract may be called a "virtual labor contract" and is only used for handling social insurance.

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