Hello,
This task would require adding custom VBA codes for each checkbox (https://www.quora.com/Is-it-possible-to-remove-hide-text-in-a-Word-document-based-on-checkboxes-If-so-how-do-you-do-that). phpdocx supports inserting an external macro from a DOCX using addMacroFromDoc (https://www.phpdocx.com/api-documentation/layout-and-general/import-macro-Word-document-with-PHP), but it doesn't support adding custom macros from code.
Regards.