Social security is paid in the first month of the year.

If the employee is absent from work for 15 days, the employer will pay social security for him in that month.

You should participate in social security normally in the month of resignation, and suspend payment of social security from the next month.

Social security shall determine the termination time according to the records of the termination certificate of the labor contract of the parties concerned. The labor contract cancellation certificate that takes effect in the current month should also be insured for employees according to normal conditions, even if they only go to work for one day.

People's Republic of China (PRC) social insurance law

Article 58 An employing unit shall, within 30 days from the date of employment, apply to the social insurance agency for social insurance registration for its employees. Without social insurance registration, the social insurance agency shall verify the social insurance premium it should pay.

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