Is it free to apply for health certificate in Shenzhen?

It's free.

Since last year, the state has issued a policy to cancel the preventive medical examination fee of the health and family planning department, and the health certificate can be processed without refund. Therefore, if you want to engage in the take-away industry, you may wish to apply for a health certificate in accordance with legal requirements. Don't be afraid of wasting time or taking the trouble to ignore the health certificate.