Dynamics 365 will integrate common modules from Dynamics AX and CRM, allowing users to choose apps from the AppSource portal. It will include modules like Sales, Customer Service, and Finance. Developers will be able to extend Dynamics 365 using tools like Visual Studio, Office 365, Power BI, Power Apps, and Azure. They can develop custom solutions and integrate data from sources like SharePoint, OneNote, and Outlook. Overall, Dynamics 365 aims to provide a unified platform for business applications and data.