I want to implement Single signOn on my web application using SAML where Azure Ad will be the Identity Provider. I need to know what is entityId, appId and and how to create metadata.xml.
The details you seek are available in this site https://learn.microsoft.com/en-us/azure/active-directory/develop/azure-ad-federation-metadata All the details present in FederationMetadata.xml file depends on what is configured on Azure AD. As a Web application developer, you don't need to create this XML file. It should be provided by the person who is managing Azure AD. If you are the person managing Azure AD also, then you can download it from there.