Add VAT Number field to Funnel Order Forms (1-step/2-step)

I want to be able to add a "VAT Number" (Numéro de TVA) field directly in the 1-step and 2-step order forms within the funnel builder. This is essential for B2B sales to allow professional customers to provide their tax information during checkout for proper invoicing and tax compliance. Currently, we have to use workarounds like separate forms, which isn't ideal for the user experience.