I haven't bought social security before. I have worked in a company for several years, and now I want to buy social security. Can the social security company make up for it a few years ago?

You can bring your ID card to the social security collection center where your previous unit was insured.

If your current unit and the original unit are not in different places, if the original unit has stopped your insurance, the new unit can directly report the increase. The original ID card is correct, and the front and rear accounts are automatically merged.

If the two units are in different places, they need to print the insurance payment voucher at the original insured place and go through the social security transfer procedures. Before the transfer, the current unit needs to increase your social security.

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