Add lead to custom taxonomy on form submission

This document shows an example plugin that will extend Inbound Forms to be able to add a lead to a custom taxonomy on form submission. This particular example adds a ‘Agents’ , ‘Source’ , ‘Unit Type’ and ‘Status’ taxonomy. It then lets ‘Agents,Source, and Status’ be set at the form level, while adding a custom form field called ‘Dropdown – Unit Types’ that allows visitors to be added to the unit type taxonomy they select.

Please give it a study and it may help you your custom taxonomy needs.