In the context of standardisation, certification refers to the attestation by a third party that a product or service meets the specific requirements of a standard.
You can apply for an attestation by a third party (laboratory, certification/inspection body) of the conformity of your product or service. This means that the conformity of this product or service is verified against the requirements of the applicable standard. Here you will find a list of accredited bodies that can certify your products.
NBN is not a certification body, so it does not issue certificates.