On iOS:
Open any book summary and tap “Read”
Tap the “Aa” icon in the top-right corner of the screen
A font settings menu will appear
Use the slider to adjust the font size to your preference
On Android:
Open any book summary and tap “Read”
Tap the “Aa” icon in the top-right corner
In the pop-up menu, use the slider to change the font size as needed
Your selected font size will be saved and applied automatically the next time you read.