The Freshdesk In-Sync App for Facebook lets you create a page tab on your brand page, and through it, allow users to seamlessly access your knowledge base, community forums and even create support requests from directly inside your Facebook page.
You can open up your self-service portal (knowledge base and forums) to your Facebook fans via the Facebook page tab in your integrated Facebook pages. The support page tab is a view of your support portal served inside Facebook through an iframe. It contains the default header from your self-service portal with the navigation bar. In addition, users will be shown their recent ticket history, a list of recent solution articles and popular topics in your community forums.
For more information visit - https://support.freshdesk.com/support/solutions/articles/126729-creating-a-branded-support-tab-on-your-facebook-page