title: How to allow external users to sign in to an app that is secure by Microsoft identity using Azure AD
body: <p>I have an app (ASP.Net Classic) that is using Azure AD authentication. Now, we want to allow user outside of the organization to sign in.  I read few document B2C and B2B, but I am unable to see which one to good for me.</p>
  <p>I am looking that  members in the organization should sign in and doesn't have to create new account.   One of the option B2B suggested that to add user to in AD as a guest user but this is the manual process, it would be good if it can be automated. Also that doesn't describe how user would send the request to for login info.</p>