The biggest challenge of moving from SharePoint On-premises to Office 365 SharePoint online is data import and integration. Populating Office 365 lists and libraries with data from external sources is no easy task because your office 365 online is completely disconnected from your other sources of data such as your business applications that may be residing on-premises. In order to fully take advantage of the sharing and collaboration features of Office 365 SharePoint online, you need to have the right tools and resources to move your data from on-premises to the lists and libraries in SharePoint online. For example, you may want to move data from your SQL server or Exchange Server on-premises to SharePoint online Lists and document libraries.