Choose the Right Message Format

What it is

Outlook supports three message formats for composing emails:

  • HTML (HyperText Markup Language): The recommended format that supports text formatting, styles, images, and accessibility features
  • Plain Text: Basic text-only format without any formatting or structure
  • Rich Text Format (RTF): Microsoft-specific format primarily for internal Exchange communications

The message format determines what accessibility features are available when composing emails. HTML format provides the most comprehensive accessibility support.

Why it matters

Choosing HTML format is essential for email accessibility because it:

  • Enables semantic structure: Allows use of proper heading levels, lists, and other structural elements that assistive technologies can interpret
  • Supports styling: Enables proper formatting that helps all users, including those with cognitive or reading disabilities
  • Allows alternative text: Enables you to add alt text to images for screen reader users
  • Provides better navigation: Screen readers can navigate HTML structure more effectively than plain text
  • Works across clients: HTML is widely supported by all modern email clients and webmail systems

Why not plain text?

While plain text may seem simpler, it lacks the semantic structure that assistive technologies rely on. Without headings, lists, and proper formatting, screen reader users cannot efficiently navigate or understand your email's organization.

How to set HTML as default

Setting HTML as your default message format

  1. Open Outlook
  2. Go to File > Options
  3. Select Mail in the left sidebar
  4. Under "Compose messages," find the Compose messages in this format dropdown
  5. Select HTML
  6. Click OK to save your settings

   Verification

After setting HTML as your default:

  • New emails will automatically open in HTML format
  • You'll see formatting options in the ribbon (Font, Styles, etc.)
  • The Format Text tab will show HTML-specific features

Changing format for a specific email

If you need to change the format of an individual email:

  1. Open or create the email
  2. Go to the Format Text tab
  3. In the Format group, click HTML, Plain Text, or Rich Text

Note about replies and forwards

When you reply to or forward an email, Outlook uses the same format as the original message. If you need to add accessibility features to a plain text reply, convert it to HTML format first using the steps above.

Format comparison

Feature HTML Plain Text Rich Text
Heading styles
Bulleted/numbered lists
Alternative text for images
Table structure
Cross-platform compatibility Excellent Universal Limited
Recommended for accessibility Yes No Only for internal use

Best practice

Always use HTML format for accessible emails. It provides the necessary features to create properly structured, navigable emails that work with assistive technologies.

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