Billing field names added by POP at checkout

Configurationwordpress2026-07-01

Goal

Know the technical names (name/meta key) of the fields POP adds to WooCommerce checkout, useful if you customize the theme, a custom checkout plugin, or read order meta via code.

Fields added

Field	What it contains
`billing_choice_type`	Document choice: `receipt` or `invoice`. Visible only if the choice is enabled (see below).
`billing_invoice_type`	Customer type: `private`, `company`, or `freelance` — fixed keys, even if you customize the labels.
`billing_sdi_type`	A single field for either PEC or the 7-character SDI recipient code (these are not two separate fields).
`billing_vat_number`	VAT number.
`billing_tax_code`	Tax code (codice fiscale).

A format check (RegEx) is applied to the billing_sdi_type, billing_vat_number, and billing_tax_code fields, in addition to any required-field setting, which varies by country and customer type.

Where visibility/labels are configured

All of these behaviors are set in POP → Electronic Invoice - Settings, Checkout tab:

Customer type list — customizes the labels of billing_invoice_type (the private, company, freelance keys stay fixed); format: one line per entry, key:Label.
Activate the choice of receipt — shows/hides the billing_choice_type field.
Disable PEC/unique code field — hides billing_sdi_type (the recipient code is automatically set to 0000000).
Disable Fiscal Code — hides billing_tax_code for companies and freelancers.
VAT number and tax code for non-EU customers — shows/hides these fields for non-EU customers.
Position of the fields (e-invoice) in the checkout form — positions the field block at the top or bottom of the form.

Verify

Inspect the checkout HTML (or the order meta in wp-admin > Orders) and check that the field names match exactly what’s in the table.

Common errors

A custom plugin/theme can’t find the PEC field — it probably looks for billing_pec: the correct name is billing_sdi_type (used for both PEC and the SDI code).
You’re looking for billing_cf — the actual name is billing_tax_code.
The meta saved on the order doesn’t match what was entered at checkout — if you use a custom checkout plugin, compatibility with these fields isn’t guaranteed: POP can’t account for third-party logic that alters the order flow.

To add custom logic based on these fields (e.g. via the wc_el_inv-* hooks) see custom-code-snippets.