How to write the social security certificate of the company?

Social security can be used as one of the evidences to prove the labor relationship, but it can't be concluded that there is a labor relationship between the two sides only by social security. If your company has no labor relationship with Party A, you can ask Party A to issue a statement, explain clearly the cause and effect of attaching social security, and write and sign it in person. If the employee advocates establishing labor relations with social security in the future, it will not be supported. However, it is still risky to buy social security on behalf of others, which is not recommended.

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