Here’s how:

Double-click a friend’s name in your Messenger list. This opens a conversation window.

Do you see pull-down menus for font and font SIZE under the main text area? If not, click the palette icon—it has a T on it.

Pull-down menus should now appear below the main text area of the conversation window (where you read messages). Click the font pull-down to choose the font you like, and the size pull-down to adjust the size.

You can also pick a color for the font by clicking the palette button. This opens a column of colors for you to choose from. Not seeing a color you like? OK, click Other Colors… to look at other options. Finally, if you want to type in a rainbow of colors or in any combination of colors you put together, click Color Effects…. Funky fun! You can name and save different combinations to use them again later, like “Underwater” for a collection of blue tones, or “sweden” for blue and yellow.