Office 2013 programs such as PowerPoint 2013 work with their own Accounts system. Additionally, they also integrate with the Account you use to sign in within your Windows-based operating system. Many options within PowerPoint show up or change depending on which Account you are signed into, and these include your Recent Files list, your connected services, and even the interface color for your program. While these customizations show up irrespective of whether you are running PowerPoint 2013 on Windows 7 or a newer version such as Windows 10 or 8, the process in which you sign in and switch Accounts differs.
Learn how to sign out and switch Microsoft Accounts in PowerPoint 2013 for Windows.

