I want to call my friend's company to buy social security. What should I do? What are the processes?

Individual affiliated units handle social security in the name of human resources companies. Individuals sign agency contracts with human resources agency companies, submit relevant materials, and pay social security fees and service fees. (Social insurance premium: composed of enterprise payment part and individual payment part), which is purchased by the unit to which the individual belongs, and the total social insurance premium is paid by the individual. The agency pays social security fees for individuals on a monthly basis. Individuals can check the details of social security purchased by themselves on the social security bureau network (or local tax network) and get the social security card the next month (before). People who need to buy social security from affiliated units: freelancers, entrepreneurs, flexible employees, temporarily unemployed or short-term workers.

I want to buy social security from a human resources company in my own name, mainly because I want to enjoy: old-age insurance, maternity insurance and medical insurance. There is also no work-related injury and unemployment insurance (both work-related injury and unemployment insurance are paid by the company for employees, but there is no labor relationship between the individual and the human resources company, and the agency company cannot prove that the individual has a work-related injury or is unemployed without his will).