If you sign in to any Microsoft service you must have to be a Microsoft account.
If you have yet not created just create It.You can also create email id using your existing email id like firstname.lastname@example.org.
If you don’t have any email id you can create Microsoft email id itself go through https://signup.live.com
Overview of benefits are:
Microsoft Apps Store: Once login you can easy access all things digital while protecting your personal information.
OneDrive : It works like Google Drive and Dropbox here is limit are for personal users 5 Gb Free.
Bing Search engine: personalize your search result so you can find what you are looking for faster.
MSN : Categories your collections of News, Sports, Weathers, Entertainment and mores.
MS Office: You can easily sync your all office docs across your devices like Mobile, Laptop and tablets on easy go.
Outlook.com: Microsoft developed web based portal which looks like offline MS outlook. Where you can sync your offline Task, Calendar, People very easily.
Skype : This is the one of the popular apps of Microsoft, you can use it for Calling (Video & Audio), Messaging and File/Screen sharing purposes.
Xbox Live : Play games with your family and friends and also you may connect with massive community of player worldwide.