A Help Center is organized into categories and sections holding individual articles, with a theme you can customize to match your branding. Customers can browse or search it, and depending on your settings, leave feedback or vote on whether an article helped.
You can run more than one Help Center if you support multiple brands, and control whether each one (or specific sections within it) is public or restricted to signed-in users. When an article genuinely doesn't answer the question, a contact form or widget lets the customer submit a ticket directly, so self-service and ticketing aren't separate systems, just two ways into the same one.
The Help Center API lets you create, update, and read articles programmatically rather than only through the admin editor, which is what makes syncing content from somewhere else even possible.