> ## Documentation Index
> Fetch the complete documentation index at: https://billing-help.nace.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Welcome

> Billing team guide to NAPA and the Billing app

## Welcome to NACE Billing docs

This site is your guide to **NAPA** (our billing automation) and the **Billing app** (the tool you use to upload documents, review invoices, and handle approvals).

## What you'll find here

<CardGroup cols={3}>
  <Card title="NAPA & Billing" icon="receipt" href="/billing/overview">
    What NAPA does, how invoices are created, and how the process works from contract and timesheet to delivery.
  </Card>

  <Card title="Billing app" icon="window" href="/frontend/overview">
    How to use the billing app: uploads, review, approval, and where to log in (test, demo, or production).
  </Card>

  <Card title="Help" icon="circle-question" href="/help/contacts">
    Who to contact for access, technical issues, or questions.
  </Card>
</CardGroup>

## Quick links

* **What is NAPA?** — [Billing overview](/billing/overview) · [How to use NAPA](/billing/napa)
* **Using the app** — [Billing app overview](/frontend/overview) · [Using the Billing app](/frontend/using-the-app)
* **Environments** — [Test, Demo, and Production](/frontend/environments)
* **Disputes** — [Dispute resolution](/billing/disputes) · [Get help](/help/contacts)