You don't have to strain your eyes to read your messages anymore. Choose a font size that you prefer, so you don't miss any details. You can always change it again at any time.
Choose from four font sizes: Small, Regular (default setting), Medium, and Large. Select a size that’s comfortable to your eyes.
Changing the font size only applies to message text, not to attachments, images, or files.
To select a preferred font size using Dynamic Type on iOS devices, see Adjust the font size.
Click your profile picture, then click .
Go to Font size for messages, and drag the slider to select the size you prefer.
Then, click Save.
If you restart or exit the app, it remembers the last font size you had selected.