A Microsoft account is what you use for almost everything you do with Microsoft devices and services. It’s an email address and password that you use to sign in to Skype, Outlook.com, OneDrive, Windows Phone, and Xbox LIVE – and it means your files, photos, contacts and settings can follow you to any device. Microsoft account used to be called "Windows Live ID".
If you already use an email address and password to sign in to Microsoft devices and services, then you already have a Microsoft account.
If you want to use your Microsoft account to sign in to an existing Skype account, you can link your Skype account with your Microsoft account – that way you only have one password to remember.
You can sign in to Skype with your Microsoft account on any device or operating system, not just those running Windows – so if you use a Mac, iOS, or Android device, you can use your Microsoft account to sign in to Skype.
Yes – Microsoft account gives you enhanced security and privacy. It also means that if you forget your password, it’s easier to recover it.
Find out more about the benefits of a Microsoft account on microsoft.com.