---
title: "Email-to-fax instructions"
slug: "email-to-fax-instruction"
updated: 2026-06-18T14:30:27Z
published: 2026-06-18T14:30:27Z
canonical: "docs.ucstack.io/email-to-fax-instruction"
stale: true
---

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

# Email-to-fax instructions

## Sending a Fax via Email

This article explains how to send a fax directly from your email. By following a specific addressing format, you can bypass the need for a traditional fax machine and transmit documents as faxes with just a few clicks from your own mailbox.

### Steps

1. From your email client (Outlook, Gmail, etc.)
2. Start a new email.
3. In the **TO** field, enter the fax destination in the following format:
  1. **FaxNumber@yourfaxdomain.com**
  2. Example: **5141239876@yourfaxdomain.com**
  3. Please use the fax domain *(@yourfaxdomain.com)* **that was given to you at signup**
4. Attach the document(s) you want to fax
  1. Maximum file size: **10MB**
  2. Cannot be protected by a password
  3. Attachment file name needs to be:
    1. Without space
    2. Without special characters
    3. Use underscore “ _ “ if needed
    4. Example: **My_Fax_Document.doc**
5. Optionally enter a subject or message body
6. Send the email

### Email-to-Fax Without Attachments

Email-to-fax now supports sending faxes even when no file is attached, provided the “**Email Body As Cover Page**” setting is enabled. This prevents failed or silent sends when users submit fax requests using only email text.

![](https://cdn.us.document360.io/3aabdf30-3e12-42ad-8192-dd2610fd289c/Images/Documentation/image(957).png)

Your email will be converted and transmitted as a fax to the destination number.

### Supported Attachment Types

The following file types are supported for Email-to-Fax:

- PDF
- DOC
- DOCX
- JPG
- JPEG
- PNG
- TIF
- TIFF

### Special Notes and Settings

- Make sure your attached documents are not protected by a password
- Sending large image files (such as high-resolution photos) is **not recommended**, as they can cause transmission delays or conversion errors, which may result with sending failures

### Email Notification

Upon processing, a confirmation email regarding the fax status will be sent to you.

![](https://cdn.us.document360.io/3aabdf30-3e12-42ad-8192-dd2610fd289c/Images/Documentation/image(958).png)

---

### FAQ

#### I received a failure email. What should I do?

First, check the reason provided in the email. Then try the following:

- Confirm the fax number is correct (including area code and any prefixes).
- Make sure the number is a fax line, not a voice line. You may verify this by calling from your phone (cellular or desk phone).
- Try sending again after a few minutes.
- If the problem persist, contact your respective Technical Support representative.

#### Are there file size limits for attachments?

Yes. While we supports several file types, large or image-heavy files may cause delays or failures.

📎 Attachments size limit is **10 MB**

Please avoid high-resolution photos when possible.

#### Why didn't my attachment go through?

This usually happens if:

- The file type is not supported.
- The attachment file name contains a space or a special character
- The file is corrupted or password-protected.
- The attachment was missing or not properly added.
- The attachment was over 10 MB

✅ Always double-check that your document is attached before hitting send.