> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pasca.name.ng/llms.txt
> Use this file to discover all available pages before exploring further.

# Invoices

> Build, validate, and sign compliant invoices

## Purpose

Use the invoice endpoints to validate payloads, sign invoices, and retrieve stored invoices. PASCA expects a structured invoice document with supplier and customer parties, line items, totals, and tax information.

## Recommended flow

1. Validate the invoice payload with `POST /api/v1/einvoice/validate`.
2. Sign the invoice with `POST /api/v1/einvoice/sign` to generate the IRN.
3. Use the IRN for transmission, updates, and retrieval.

## Key fields to prepare

* `business_id`: PASCA business identifier.
* `irn`: Your invoice reference number.
* `invoice_type_code`: Invoice type from the resources endpoint.
* `document_currency_code`: Invoice currency.
* `accounting_supplier_party`: Supplier identity and address.
* `accounting_customer_party`: Customer identity and address.
* `invoice_line`: Line items with quantities and pricing.
* `legal_monetary_total`: Summary totals.