There are two kinds of certificates for electricians and welders, namely, special operation certificate (post certificate) and professional qualification certificate (grade certificate), which are issued by the safety production supervision and management department and the labor and social security department respectively.
Grade certificate and employment certificate are issued by two departments and must be held according to regulations.
Ask the Labor Bureau and the Safety Supervision Bureau. Many schools, or you can go to the local information port to search.
Generally around 500 yuan, the study time is one month.