Certification bodies require the license to perform the certification audit in the organization, the required license is called Accreditation. The license is provide by the accreditation board (like: JAS-ANZ, UKAS, etc.) to the certification bodies. The certification bodies need to be compliant with ISO 17021 standard if they want accreditation for management system. Accreditation bodies also need to be compliant with a standard ISO 17011, a standard which defines the process of accreditation.
There is usually only one accreditation board in the country, such as India has NABCB. While there are several certification bodies in the country with the different accreditation. For example : Bureau Veritas, TUV, TNV, BSI, etc. Are some of the well known certification bodies.
After getting the accreditation the certification bodies are able to perform the certification audit in the organizations. During the ISO certification audit the management system of the organization need to be comply with the required ISO standard. The certificate is issued after the certification audit if required ISO standard is in place.