To change the color theme, select an option from the “Office Theme” drop-down list. If you use a local account in Windows 10, or you’re using an earlier version of Windows, you can access the Office Background feature by signing into your Microsoft account in any Office program, using the “Sign in” link on the right side of the title bar. If you’ve signed in to Windows 10 using your Microsoft account, you should have access to the Office Background option, unless you specifically sign out of Office. The Office Background feature is only available when you are signed into your Microsoft account. If you don’t see a background image on the title and the Office Background drop-down list is not available on the Options dialog box, that means you aren’t signed into your Microsoft account in Office.
