Outlook is often used mainly as an

• email application,
• it also includes a calendar,
• task manager, contact manager,
• note taking,
• journal,
• web browsing.

It can be used as a stand-alone application, or can work with Microsoft Exchange Server and Microsoft SharePoint Server for multiple users in an organization, such as shared mailboxes and calendars, Exchange public folders, SharePoint lists, and meeting schedules. Microsoft has also released mobile applications for most mobile platforms, including iOS and Android. Developers can also create their own custom software that works with Outlook and Office components using Microsoft Visual Studio. In addition, mobile devices can synchronize almost all Outlook data to Outlook Mobile.