Alternative text (alt text) is descriptive text conveying the meaning of an image. When screen readers like Microsoft Narrator, JAWS, and NVDA reach content with alt text, the alt text is read aloud so people with visual impairments can better understand what’s on the screen. Well-written, descriptive alt text dramatically reduces ambiguity and improves user experience.

The Microsoft 365 Accessibility checker reviews visual content for alt text, offers suggestions on improving content accessibility, and provides both an automatic alt text generator, and a manual alt text editor.

This is a good option for finding and adding alt text to images in existing documents.

First, open the Microsoft 365 Accessibility Checker

1. In Outlook, Word, Excel, PowerPoint, and OneNote: on the Review tab, select Check Accessibility.
2. In the right Accessibility pane, issues with accessibility appear under Inspection Results.
3. Select any flagged issues to see recommended actions.

Next, manually view and edit alt text or approve automatic alt text

1. Right-click an image, chart, or other object, and select View Alt Text. Tip: On the Review tab, you select Check Accessibility drop down and choose Alt Text.
2. In the Alt text pane on the right, edit or approve the displayed alt text (if automatically generated).
3. If the image doesn’t need alt text, such as a border, select Mark as decorative.

How to turn automatically generated alt text on or off:

1. On the File tab, select Options and choose the Accessibility
2. Select or clear the Automatically generate alt text for me checkbox under Automatic Alt Text.

Source: “Everything you need to know to write effective alt text,” Microsoft Support.

See also: “Improve accessibility with the Accessibility Checker”, Microsoft Support.