If you want to create a document that contains checkbox images rather than “True” or “False” values, you can do so in two different ways.
The easiest way is to add the "checkbox" merge field attribute to any boolean field that you want to display as a checked or unchecked checkbox. If your merge field looked like this:
You can display it as a checkbox image by adding the attribute to the end like so:
Learn more about merge field attributes here.
Checkboxes can also be displayed using CSS styling similar to the following example:
You can also display checkboxes by leveraging a formula field.
By adding the following formula field to your object, you can easily leverage it to place checkbox images into your S-Docs. (You do not need to add the field to the page layout.)