When do I need to use authToken

In the documentation Getting Started - Amity Docs I see there’s authToken that can be passed - where do I get the token and in what occasion do I need to pass it here

Auth token will be required if you enable 'Secure Mode" on the Console - and you will need to pass auth token you got from your backend (by calling our server API - Security - Amity Docs) when calling registerDevice or you’ll get 401 unauthenticated error.