how to set global default font for user text in form; Acrobat DC

"but you have to divide the rgb value by 255 to get the Adobe Javascript value you need to get the color you want. "

No, JavaScript is able to divide RGB values, so you don't have to:

f.textColor = ["RGB", 5/255, 18/255, 191/255];

Actually, you can do what you want by creating a New Action in Action Wizard and using the following Adobe JavaScript.   Go to Tools > Action Wizard > New Action > More Tools > Execute JavaScript > click on the circle with a plus sign and an arrow beneath it > click on Specify Settings > paste the provided Adobe JavaScript in the Click and Edit JavaScripts box > click OK > click on Save > give the action a name like Auto Detect Font Changer > click on Save.

for (var i = 0; i < numFields; i++) {

    var fName = getNthFieldName(i);

    var f = getField(fName);

    if (f.type === "text") {

f.alignment ="left";

f.textFont = "Calibri";

f.textSize = 10;

f.textColor = ["RGB",0,0,0.545];

        // Other properties go here

    }

}

Open the document you want to perform font type, size, and color change per user typed field, under the Action List click on Auto Detect Font Changer > click Start > and your user typed fields should now be Calibri, font size 10, font color dark blue.  To confirm that the user typed fields are Calibri, font size 10, font color dark blue, close the Action List, choose Prepare Form, right click on a user typed field, choose Properties from the pop-up menu, and under the Appearance tab you should see Text with a Font Size 10, Color Dark Blue, and Font Type Calibri.  I've tested this Auto Detect Font Changer action on a Word 2007 docx to PDF doc I'm working on and I successfully get the results you want.

Based on my newbie research, which you may know already, I learned there's JavaScript and there's Adobe JavaScript, which I gather have similarities and differences.  When it comes to color changes, you can use HTML red,green,blue values as a reference, but you have to divide the rgb value by 255 to get the Adobe Javascript value you need to get the color you want.  So, HTML Dark Blue is rgb (0,0,139), but Adobe JavaScript Dark Blue is rgb (0,0,0.545).

Also, the // in the Adobe JavaScript code are ignored when it comes to executing the code.  Although, they can prevent code from being executed if placed in front of it.  The // kind of act as the old DOS REM statement code where you can state the purpose of certain commands and code strings.

Hopefully that script and info help.

How are you adding the fields to the file?