Why is the social security fee paid by local tax?

Social insurance premiums are declared in local taxes. You can manually change the amount and personnel, which is not automatically generated. However, because all units have handled the tripartite agreement, they are all withheld by the bank. Although the social insurance premium is declared together with the local tax system, the old-age insurance premium is not withheld by tax, but directly deducted by social security, and the money is credited to the social security account.

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