My issue is two-fold here, and perhaps there is one answer that connects to both problems....
1. When I add a Text Field onto stage, and right click over this text field, I cannot add an Insertion Point in order to display placeholder text
2. When I add a subform onto stage, I can then add an Insertion Point within the subform, but when I preview as PDF or save this document as a PDF, and click over the place holder text it does not go away. It remains there.
What am I missing in order to have the Placeholder text go away once a user clicks on it?
I discovered that my area of concern was not with insertion points, but with setting a pattern on a text field through the object panel. I can now display placeholder text, which will then go away once the user types into the field.