Like its predecessor, Microsoft’s Windows 10 is an operating system highly powered by the cloud. Now more than ever, if you don’t have an internet connection (unless you’re doing something specific), there is not a lot of work you can get done.
In Windows 8, along with local accounts, Microsoft also introduced the ability for users to create profiles using a Microsoft Account. For those who still need some clarification, if you own an Outlook, Hotmail, Live, or MSN email address, you already have a Microsoft Account.
Unlike a local account, which everyone have been using for a very long time, with a Microsoft Account you can sync your settings across desktops, laptops, and phones. Settings include the current theme you’re using, web browser settings, passwords, language preferences, and general Windows settings.
Source: iMore