Let’s take a look at how to change the font color in the Curtain App .
First open a document on the curtain app, then long press on the text you want to set to red font
Three options will appear above the text. Click "Select All" among them.
After selecting the text you want to set in red, click the "Font" menu. See the picture below for the location.
Open the "Font" menu and click the red color you want to set.
Then look at the selected text. They have changed from black to red.