In the US alone at least 12 million people use a screen reader, a screen magnifier or braille to read email, so it's best to make any email sent to a broad distribution accessible to people with limited or no vision. We'll use Outlook to show techniques for creating accessible messages, but these guidelines apply to any email program.
Nearly, all assistive technology is designed to work well with HTML rather than plain text. With HTML, your messages can include formatted links with display text, lists, headings and alt text for images.
To set HTML as my default format in Outlook I select File>Options and Mail. Under Compose messages I select HTML. Now any new messages I create, will be in HTML format.
If I need to reply to a message I've received in plain text, I won't be able to apply any formatting. So I select Format Text and then HTML. Now I can format this state in bold and add a hyperlink to the conference centers website.
Font choice in email messages can make a big difference for people with dyslexia. Avoid serif fonts, which include tiny tails at the beginning or end of a letter. Serif fonts are also drawn with both thick and thin lines, which can be difficult for people with dyslexia to read. Instead choose a simple sans serif font. Sans serif fonts are drawn with more consistent line widths throughout the letter. Avoid italics, fancy script, or decorative fonts with curly edges. And always use a font size of 12 points or larger. I've decided to use 12 point Segoe UI in my messages. I can set the font for a specific message by just changing it on-the-fly in the font and font size boxes. For emphasis I use a combination of color, size and bold formatting, because color alone might not be enough for people with color blindness to see a difference.
Instead of changing the font each time I create a new message, I can set it once as my default for all messages. I select File>Options, and then Mail. Under compose mail I select Stationery and Fonts. Under Personal Stationery I change the Font to 12 point Segoe UI for new mail messages. And for replying or forwarding messages.
Now all my messages will be formatted with 12 point Segoe UI. I use the same font guidelines in my signature. Under Compose messages, I select Signatures, I type the signature I want and then I set the font 12 point Segoe UI. I am also including my company logo with my signature. I add alt text to describe it, for people who use screen readers.
I also keep the background of my messages simple and clean, so the text stands out. A solid color that contrasts with the text works well and I stay away from background images. I can choose or remove email themes here. I select Personal Stationery and then Themes. Some of these work well, with strong color contrast and no background images or lines to interfere with the text. Others are way too busy to be accessible. So, I select no theme.
With these simple steps I've made sure that my emails are accessible to all my recipients.
To learn more, visit aka.ms/OfficeAccessibility.