What are the different types of digital signature certificates?

Class 0 Certificate: This certificate shall be issued only for demonstration/ test purposes.
Class 1 Certificate: Class 1 certificates shall be issued to individuals/private subscribers. These certificates will confirm that user's name (or alias) and E-mail address form an unambiguous subject within the Certifying Authorities database.
Class 2 Certificate: These certificates will be issued for both business personnel and private individuals use. These certificates will confirm that the information in the application provided by the subscriber does not conflict with the information in well-recognized consumer databases.
Class 3 Certificate: This certificate will be issued to individuals as well as organizations. As these are high assurance certificates, primarily intended for e-commerce applications, they shall be issued to individuals only on their personal (physical) appearance before the Certifying Authorities.

DSCs can be used for e-filing of income tax returns, e-tendering on websites of government departments and ministries like Indian Railway Catering and Tourism Corporation, Director General of Foreign Trade, Ministry of Corporate Affairs and Registrar of Companies.

Class I DSCs can be used by employers while communicating with employees via email. Class I certificates shall be issued to individuals/private subscribers. These certificates will confirm that user’s name (or alias) and email address form an unambiguous subject within the certifying authorities’ database.

Class II DSCs are applicable in e-filing of income tax returns & sales tax returns, etc.

Class III DSCs can be used to participate in e-tendering or e-auctions organised by governments or public sector companies.