We've written some new documentation that shows how you can set up Radio Button logic for a group of checkboxes, so that only one checkbox can be checked at a time:
You can create a radio button group with a String field that has multiple Field Options. Then you can create multiple checkbox fields with "Equals" conditions, so that a check mark is only shown when the field is a certain value. Radio buttons are just one of the things you can set up using these features. Note that you are not limited to "radio button" logic. You could also check multiple checkboxes for a single value, or set up advanced logic using regular expression conditions.
We've also added support for "Divided Comb Fields", which are commonly used for SSNs on government forms:
You can now use DocSpring's "Comb Cells" and "Comb Offset" options to fill out these comb fields that are divided into multiple sections.