Onion sites are websites that are only accessible over the Tor network. Onion services obfuscate your metadata and offer end-to-end encryption. Site administrators can now easily acquire a DV certificate for your v3 onion site using HARICA, a Root CA Operator founded by Academic Network (GUnet), a civil society nonprofit from Greece. New Onion Zine and updated onion service documentation in the Tor Project Community Portal have been developed with the support of Digital Defenders Partnership. New onion site setup guides are available in English, Spanish, Portuguese, and English.
Source: https://www.helpnetsecurity.com/2021/03/26/how-to-get-affordable-dv-certificates-for-onion-sites/