# Email threads

Follow supplier conversations tied to an invoice.

When an invoice arrives **by email**, Cortena extracts the attachment and shows structured fields for review and booking. Sometimes you also need the **email context**: who wrote what, approval questions, payment instructions in the message body, or follow-up replies in the same chain.

**Email threads on invoices** let you read that conversation **inside the invoice detail view**, without leaving Cortena or searching your mailbox.

## How to open the email thread

1. Go to **Payables → Invoices** and select an invoice.
2. Confirm the invoice was received by email. The header shows an **Email** badge alongside **Invoice** and your workflow status (for example **Ready**).
3. **Click the Email badge** to open the **Originating email** split pane.
4. The pane appears **above** the extracted invoice fields. Drag the divider between email and extraction to resize. Cortena remembers your preferred height.
5. **Click Email again** to hide the pane.

The **Email** badge only appears for invoices whose source is email. Uploads, API imports, and other channels do not show this control.

![Invoice detail header with Email badge](https://help.cortena.ai/assets/img/help/email-threads/01-invoice-email-badge.png)

## What you see in the email pane

### Conversation list

- If Cortena finds **more than one related message**, a **Conversation (n)** strip lists them in chronological order.
- Each row shows **date/time**, **sender**, and **subject**.
- The message linked to **this invoice** is marked as the current one.
- **Click a row** to load that message's body and headers below.

If there is only **one** email, the conversation strip is hidden and you see that message directly.

### Email headers

For the selected message, Cortena shows subject, date, **From**, **To**, and when present **Cc** and **Bcc**.

### Message body

The body appears in a scrollable area below the headers. Cortena loads the body when you select a message (or when the pane first opens), so longer threads stay responsive.

![Originating email pane with first message](https://help.cortena.ai/assets/img/help/email-threads/02-email-thread-first-message.png)

![Conversation list with a reply selected](https://help.cortena.ai/assets/img/help/email-threads/03-email-thread-reply-message.png)

## Which emails appear in a thread?

Cortena builds the conversation from standard email threading headers:

- **Message-ID** · unique identifier for each email
- **In-Reply-To** · points to the message being answered
- **References** · lists earlier messages in the chain

When you open an invoice, Cortena looks up other inbound emails in your tenant that belong to the same thread. Those messages are shown together, oldest first, up to **50 messages** per thread.

**Included:** inbound emails processed by Cortena for your tenant, replies and forwards that share threading headers, and the message that carried this invoice attachment.

**Not included:** mail that never reached Cortena, messages from other tenants (threads are tenant-scoped), or unrelated emails that only share a subject line.

## Why email text or graphics may look simplified

Cortena displays a **safe, read-only copy** of what was stored when the message was imported. That is intentional for security, but the view can differ from Outlook or Gmail.

- If there is no usable HTML body, Cortena shows **plain text** (reply markers, attachment names as text, simpler spacing).
- When HTML is available, it renders in a **sandboxed viewer**: external images may not load, complex CSS may collapse, and interactive elements are disabled.

**What you can rely on:** headers for routing context, message text for instructions, and the **PDF / invoice attachment** in Cortena's document preview for line items and totals.

## Tips

- If the next invoice is also email-sourced, the pane stays open and loads that thread. For non-email invoices, the pane closes automatically.
- Reading emails is **read-only**. It does not re-run extraction or move workflow status.
- For invoice amounts and legal wording, always trust the attachment preview and extracted fields.