This tool is a companion to my Convert Wingdings Characters to Check-Boxes or Radio-Buttons tool, only this one identifies sequences of two or more underscore ("_") character in a file (using any font) and places text fields on top of them, with 100% accuracy.

Each text field it adds has a unique name, so there are no duplicates.

Using this tool is easy. In the form layout stage (using Word, for example), simply add a sequence of underscore characters, without any spaces between them, at the desired width for the fields.
Here's an example file I created:

Then convert your file to PDF and run the script on it from within Acrobat (can be seen on the right in this screenshot):

It picks up the sequences of underscores and adds text fields above them:

As can be seem , each field has a unique name:

This tool can even be used in the free Adobe Reader (version XI or higher)!