How do I add alt text to images in a document before exporting it?
Quick answer
Before exporting, review each image: write a concise description for visuals that add information, and mark purely decorative visuals as decorative when your editor supports it. In supported Microsoft 365 apps, select an object and use View Alt Text or its formatting menu to add a description. Export the document as an accessible, tagged PDF where available, then inspect the PDF rather than assuming the descriptions transferred correctly. [S1] [S2]
The question, the details, the next step.
What should I do first? I have a document with photos, a chart, and a few small decorative icons.
Make an image inventory and decide what each visual contributes in context. If a photo or chart communicates information that a reader needs, give it a concise description of that information. If an icon is purely decorative and adds nothing, mark it as decorative instead of writing a description, where your editor offers that option. Microsoft’s guidance recommends concise descriptions, generally one or two sentences, and says purely decorative visuals should be marked decorative. [S1]
A useful test is: if the image disappeared, would a reader lose information needed to understand the document? If yes, describe the relevant information. If no, it may be decorative. This is a drafting aid, not a formal accessibility test.
How do I add the descriptions in the document editor?
In supported Microsoft 365 apps, select an image or other object, then look for “View Alt Text” or an Alt Text option in the object-format menu. Enter a concise description in the field. The exact menu can vary by app and version, so if those labels are absent, check that editor’s accessibility or object-format controls. [S1]
Describe the image’s useful meaning, not every visible detail. For example, if a chart in a report shows quarterly sales rising, a draft might be: “Quarterly sales rise from Q1 to Q4.” That is a hypothetical wording example; replace it with what the chart actually shows. For a photo, name its relevant subject or action rather than starting with “image of,” unless that wording helps the reader.
What if the image is a chart or repeats information already stated in the nearby text?
For a chart, focus the description on the takeaway a reader would otherwise miss; don’t guess at values or trends. If the surrounding text already explains the same point, write a description that adds useful context without needlessly repeating the whole paragraph. If the image contains complex information, a short alt text description may not convey everything; keep the full explanation available in the document’s regular text as appropriate.
For an image that adds no information at all, use the editor’s decorative setting if available, rather than an empty or vague description. Microsoft’s guidance supports marking purely decorative visuals as decorative, but it does not establish the right wording for every image or guarantee that a description captures all complex visual information. [S1]
How can I check the descriptions after exporting to PDF?
Where your Office export options provide it, export to PDF with accessibility tags enabled. Microsoft describes tagged PDF export as supporting navigation for items such as links, bookmarks, tables of contents, and alt text. Then inspect the resulting PDF: check that informative images have their descriptions and decorative images are handled as intended. Do not assume the descriptions transferred correctly just because they were present in the source document. [S2]
A practical final pass is to compare the PDF against your image inventory, especially after any layout changes. The cited guidance does not guarantee that every visual’s description will be preserved correctly in every PDF output, and the available controls vary by software. [S2]
A practical checklist
List each image, chart, and icon; note whether it conveys information.
Write a concise, accurate description for each informative visual.
Mark purely decorative visuals as decorative when the editor supports it.
Use your editor’s Alt Text controls and check that descriptions were saved.
Export with accessibility tags when available, then inspect the PDF itself.
A few more useful answers
Should every image have alt text?
Not necessarily. Describe informative visuals; mark purely decorative ones as decorative when your editor supports that option. [S1]
Does exporting to PDF guarantee my alt text will carry over?
No. Export with accessibility tags where available, then inspect the resulting PDF; Microsoft’s guidance says not to assume every description transferred correctly. [S2]
How long should alt text be?
Microsoft’s guidance recommends a concise description, generally one or two sentences. Include the information a reader needs, not an inventory of irrelevant visual details. [S1]
Sources
References used for this guide.
- [S1] Add alternative text to a shape, picture, chart, SmartArt graphic, or other object support.microsoft.com · Checked
- [S2] Create accessible PDFs support.microsoft.com · Checked