This article clarifies whether it is possible to add a default role to a new user on the first login. Users may need to be created with a specific role.  

• Roles
• New User
• Action

This can be achieved in an Action with the following Post-Login Action code:
 

1.  Create an Application that will use the Action.

2. Authorize it to the API created with the required scopes. See Enable Role-Based Access Control for APIs.

3. Create an Auth0 Action.

To get an Action working in a specific flow, create the Action and then add it to a flow.

1. Navigate to Auth0 Dashboard > Actions > Library to view the list of existing Actions.
2. Select Create Action > Create Custom Action.
3. Enter a Name and select the Login / Post Login trigger since an Action will be added to the Login flow.
4. Then select Create.
    

4. Store the application’s credentials in the Action’s event.secrets object.

Use the domain, client ID, and client secret in the application settings of the app created in step 1. See Add a dependency

5. Add the auth0 npm module/ dependency.

• See Add a dependency.  

NOTE: Use the latest version of the module, leave the Version textbox blank, click on any other part of the Add Dependency dialog box, and click on the Create button.

6. Initialize and use the Management API in the Action.

Next, implement the code logic. The following sample code logic assigns a user a role based on their login count.

exports.onExecutePostLogin = async (event, api) => {
  if (event.stats.logins_count !== 1) {
    return;
  }

  const ManagementClient = require('auth0').ManagementClient;

  const management = new ManagementClient({
      domain: event.secrets.domain,
      clientId: event.secrets.clientId,
      clientSecret: event.secrets.clientSecret,
  });

  const params =  { id : event.user.user_id};
  const data = { "roles" : ["YOUR_ROLE_ID"]};

  try {
    const res = await management.assignRolestoUser(params, data)
  } catch (e) {
    console.log(e)
    // Handle error
  }
};