Microsoft Disability Answer Desk
Voice Call: 1-800-936-5900
ASL Call: 1-503-427-1234
Chat Online: support.microsoft.com/en-us/answerdesk/accessibility#
Microsoft Support Documents
Microsoft has their own support documents that cover magnification and other accessibility features available on their website. Here are links to those pages listed by operating system:
Windows 10: support.microsoft.com/en-us/help/4089827/windows-10-guide-for-people-who-are-blind-or-low-vision
Windows 8: www.microsoft.com/en-us/download/details.aspx?id=35751
Blind Support 