New select in Billing data

[jpiffaut]

Hello people,
I have a module that allows to issue different types of documents integrating with another platform.
In the installation of the module I create some tables and when configuring the module I save the configuration in these tables.
One of those fields is the type of document to issue. From the module configuration I can enable up to 4 different modules and I want to be able to show in this form, using a select the active documents to be issued.
Currently I am adding a simple field which I alter with a JavaScript when loading the form, but this generates multiple incompatibilities with other modules that modify the Prestashop checkout.
I would like to see what would you recommend me to do in these cases to be able to intervene this form keeping to a minimum the possible incompatibilities with other modules.