Editing Custom email headers (section)

=== Introduction ===
In ActiveCampaign, a '''custom email header''' is an invisible element embedded in every campaign and automation email you create. This header serves various purposes such as internal verification, tracking contacts, and managing email delivery more effectively. Though not visible to your contacts, it plays a vital role in how your email system processes incoming messages. This feature is particularly useful for organizations that need to categorize and prioritize emails based on the sender and context, such as identifying messages coming from an automated marketing platform.

For example, companies often utilize custom email headers to facilitate internal tracking. If you were to send a campaign to 10,000 internal employees, you might set up a rule on your email system to recognize and organize all emails from ActiveCampaign. A useful custom header in this instance could be:
```
Source: ActiveCampaign - %EMAIL%
```
This allows for smoother handling of emails via your organization’s email server.