For an overview on Microsoft Azure Files and Azure File Sync a great resource to understand and learn more can be found at this link:
Azure Files with Azure File Sync is a game-changer. Microsoft’s answer provides an authoritative answer and direction for using the cloud as a business file server dilemma – which is:
How do you centralize your company’s file shares in the cloud, but at the same time keep the performance of an on-premises file server?
While not first to answer this question, Microsoft’s authority and credibility legitimizes the cloud-as-a-fileserver strategy with Azure Files and Azure File Sync.