The checkbox should have an "if" ... "else" statement, something like:   if checkbox is ticked{ make field gray }   else { make field transparent }   This previous thread has an example:…

this.mailDoc({ bUI: false, cTo: "some.email@xxx.com",  //enter the destination email address here });     There are other parameters for mailDoc that you can read about in the JavaScript reference.

Press Control+J to open the JavaScript console. Are there any errors in the console when you click on the checkboxes?

Draw a link around the words "Chapter 2" with the Link tool. In the Create Link dialog that opens, you can choose "Go to a page view" to navigate to a page in the current PDF or another PDF that is…

The features you describe can be done only in LiveCycle Designer, not Adobe Acrobat Pro.   I believe LC has "sub-forms" which can be hidden and collapsed.

This may help:   Button with JavaScript Action crashes Acrobat   You can turn off the Edit > Preferences > Forms > Automatically adjust tab order when modifying fields.

How exactly are the Adobe Reader users exporting the form to TXT format?   The method to use is   …

Have you tried using Maximum Quality when saving as a JPEG? The default setting is Medium Quality.   You may also want to try saving as PNG or TIFF (depending on what the email client can accept) to…

For iOS, try PDF Expert: https://readdle.com/products/pdfexpert5

Have a look at this earlier thread on this subject:   https://forums.adobe.com/message/4902129#4902129

Click slightly outside and to the left of the checkbox to select/deselect them.