The ability to change the text size allows you to customize the readability of your chat story directly within the Style tab. You might want to make the text larger for better visibility or smaller to fit more content on the screen during preview or export.
You can access the text size options by navigating to the Style tab located at the bottom navigation bar, between Messages and Video. From there, select the Text size option, represented by the AA icon.

Once the Text size overlay appears, you will see a slider or set of options to adjust the font scale. This change affects how large the text in the chat bubbles appears on your exported video.
This article details how to modify the font scale for your chat story using the Text size setting found within the Style tab. Adjusting this option lets you control the on-screen size of all message text, ensuring optimal visual clarity for your final video export.