There are 2 main ways to change the Quran reader settings:
1- Through the Main menu
From the Dashboard, tap on the settings gear icon on the top right
Scroll down to the "Page Layout" Section
Tap on "Adaptive mode"
From there, you can increase or decrease the font and adjust the other settings to your convenience
2- From the Quran Reader:
Tap anywhere on the screen to show the Top menu bar
From there, Tap on the "Settings" gear icon on the top right
Scroll down to the "Page Layout" section
Similar to method #1, you can adjust the settings to your convenience!