Is there any way to change the font size or color of the fields?: Frequently Asked Questions: smaconne: Easily use the Notes app on your iPhone, iPad, Android and other smart devices!

Unfortunately, a field with a [Field Name] cannot have a color, etc.
For fields with a formula, you can add an HTML tag to the field as shown below to format the field in any way you want, such as font size, bold, and color.

_Subject := @GetField( "Subject" );
'<span style="font-size: 18px; font-weight: bold; color: darkred;">' + _Subject + '</span>'