I want to pay more social security how to do?

Bring your ID card and go directly to the social security office to do it, but the base of payment and the ratio will be different with the company. The only thing that you can do is to get a good deal of money from the company. If you want full coverage, it's best to hang on to the company and give them the money

Extended reading: how to buy insurance, which is good, hand in hand to teach you to avoid the insurance of these "pits"