In Zoho Directory, you can configure OpenID Connect (OIDC) for any third-party apps. The way OIDC performs vary based on the type of application you configure ZD with.
Learn how OIDC works in Zoho Directory.
Assign yourself as a user for the custom OIDC app added in Zoho Directory. Now try signing in to the third-party app using OIDC SSO.