A Certificate Authority (CA) is a trusted entity responsible for issuing and revoking digital certificates used in electronic signature processes.
Since the entry in force of the eIDAS regulation, the Certification Authority figure in the European Union has been replaced by the Qualified Services Provider (QSP).
Besides these basic functions, a Certification Authority (QSP in the EU) can provide other services, as publishing certifications, revoked certifications lists, certification validity verification services…
You can consult the certification services providers and authorities supported by Viafirma in the following link:
What Certification Services Providers and Authorities are supported by Viafirma?