To change your display in Windows, select Start > Settings > Accessibility > Text size. To make only the text on your screen larger, adjust the slider next to Text size.

Under Make text bigger on the Display tab, drag the slider to the right to increase the size of the sample text. Once you're happy with the text size, select Apply. Windows scales up the size of all text. To go …

On the slide master or layout, select the level of placeholder text for which you want to change the font size. You can also type in any size you want in multiples of .1, such as 10.3 or 105.7. The bullet …

On the Personal Stationery tab, under New mail messages or Replying or forwarding messages, choose Font. In the Font box, choose the font, style, size, and color that you want to use.

Learn how to change the font size when composing messages in Outlook on the web.

To change the size of your font when reading email, use your browser's zoom function or use the Immersive Reader. You can also customize your email and change the size of your font when …

In Outlook for Mac, you can easily choose a preferred type size and type font for text in new messages, replies and more.

Increase or decrease the font size or choose a different font for items that appear in the message list.

The Font Size list includes commonly used font point sizes, but you can type in font sizes that aren't listed. Available font sizes range from .5 point to 999.9 points.

Change the fonts in your message by selecting a new font theme. A font theme applies to all of the headings and body text in the message that you are working on.