OpenID4VCI
OpenID4VCI, OpenID for Verifiable Credential Issuance, is the protocol a wallet uses to request and receive a credential from an issuer over a standard OAuth2-based flow.
A holder starts the flow from their wallet, the issuer authenticates them and checks whatever proof it needs, then returns a signed credential in a format such as SD-JWT VC. OpenID4VCI is the issuance protocol the EUDI Wallet reference implementation is built on under eIDAS 2.0, so an issuer that supports it can reach every EU wallet without a custom integration per member state.