How to Fax a PDF (From Computer or Phone)

This guide covers step-by-step methods for both computer and phone, with specific tool recommendations for each approach.

How to Fax a PDF From Computer

Faxing a PDF from your computer requires either an online fax service or an email-to-fax feature. Both methods work through your web browser or email client—no special hardware needed.

Using an Online Fax Service

1. Choose a service (5 minutes): Most online fax services offer free trials—typically 14-30 days or a set number of free pages. Popular options include eFax, Fax.Plus, and Dropbox Fax. For a one-time fax with no account required, ThirtyFax lets you send up to 5 pages free.
2. Sign up or start sending: Create an account if required, or jump straight to sending if using a no-account service. Account-based services typically ask for payment details upfront, even during trials.
3. Upload your PDF: Click “Send Fax” or “New Fax” and upload your file. PDF is the preferred format because it preserves formatting during transmission. Most services accept files up to 20-25 MB.
4. Enter the recipient’s fax number: Type the full fax number, including area code. For international faxes, add the country code (e.g., +44 for UK, +1 for US/Canada).
5. Add a cover page (optional): Most services let you include a cover page with recipient name, subject line, and a brief message. Some add your service’s branding unless you’re on a paid plan.
6. Review and confirm: Double-check the fax number and page count. Services typically show the cost per page or confirm you’re within your plan’s limits.
7. Send the fax: Click “Send” and wait for delivery confirmation. This usually arrives within 5-10 minutes, either by email or in your service dashboard.

Pro tip: If your document isn’t already a PDF, you can save it as PDF from Microsoft Word, Google Docs, or most other programs before faxing.

Using Email-to-Fax

Email-to-fax converts your email into a fax transmission—no web portal required. You’ll need an account with a service that offers this feature (most subscription services do).

1. Open your email client: Gmail, Outlook, Apple Mail, or any other email app works. Make sure your PDF is saved somewhere accessible.
2. Attach your PDF: Click the attachment button and select your PDF. Keep it under 25 MB for Gmail or 20 MB for most Outlook accounts to avoid delivery issues.
3. Enter the fax number in the “To” field: Format it as [fax-number]@[service-domain].com. For example, with eFax, you’d send to 15551234567@efaxsend.com for a US fax number.
4. Add a subject line: This typically becomes your cover page text. Keep it brief—something like “Contract for review” or “Medical records request.”
5. Send the email: Hit send and wait for confirmation. Most services reply with a delivery receipt within a few minutes.

Note: Email-to-fax doesn’t work with cloud-share links. If your email client converts large files to Google Drive or OneDrive links, the fax service may not process them—attach the PDF directly instead.

How to Fax a PDF From Phone

Faxing a PDF from your phone requires either a dedicated fax app or a mobile-friendly online fax service. Both iPhone and Android devices support PDF access from local storage or cloud services like iCloud, Google Drive, and Dropbox.

Using a Fax App (iPhone/Android)

1. Download a fax app (3 minutes): Search “fax app” in the App Store (iOS) or Google Play (Android). Top-rated options include Fax.Plus, iFax, and eFax Mobile. Most offer free trials or a few free pages.
2. Open the app and select your PDF: Tap “Send Fax” or “New Fax.” The app will prompt you to choose a file from your phone’s storage, Files app (iOS), or cloud service. If you need to scan a paper document first, many apps include a built-in scanner.
3. Enter the recipient’s fax number: Type the full number with area code. For international faxes, include the country code.
4. Preview your PDF: Most apps show a preview before sending. Check that the pages are in the correct order and that nothing got cut off.
5. Add a cover page if needed: Optional—some apps auto-generate one from your account details, while others let you customize it.
6. Tap “Send”: Confirm the transmission and wait for delivery notification. This usually arrives as a push notification or in-app message within a few minutes.

Popular fax apps for iOS include Fax.Plus and iFax. For Android, the same services offer native apps with similar features.

Using Mobile Browser

If you don’t want to install an app, most online fax services work through your phone’s web browser.

1. Open the fax service website: Navigate to your service’s site in Safari (iOS) or Chrome (Android) and log in to your account.
2. Tap “Send Fax”: Look for the send or upload button—mobile sites usually place this prominently on the home screen.
3. Upload your PDF from phone: Tap the upload field and select your PDF from the Files app, Google Drive, or local storage. The upload process works the same as on a computer.
4. Enter the fax number: Type the recipient’s full fax number, including area code and country code if applicable.
5. Send the fax: Review the details and tap “Send.” You’ll receive confirmation by email or in your account dashboard.

Mobile browser faxing works well for occasional use, but apps offer a smoother experience if you’re faxing regularly from your phone.

How to Send a PDF to a Fax Number

Sending a PDF to a fax number is exactly the same as faxing a PDF—the online fax service converts your PDF into fax format automatically. You don’t need to do anything special.

Here’s what you need:

• Valid fax number: Must include country code if international (e.g., +44 for UK). Domestic numbers need area code.
• File size under limit: Most services cap PDFs at 20-25 MB. Email-to-fax methods often have tighter limits—Gmail caps at 25 MB, while Outlook typically stops at 20 MB.
• Fax service account or credits: Subscription services require an active plan. Pay-per-fax and no-account services like ThirtyFax let you send immediately without signing up.
• Stable internet connection: Fax transmission happens over the internet, so a dropped connection can interrupt sending.

The fax service handles conversion behind the scenes—your PDF gets translated into the format required by traditional fax machines.

Written by

Bernard Bado

I created ThirtyFax after needing to send a single fax and refusing to pay for a monthly subscription to do it. I write here about faxing, document workflows, and the surprisingly stubborn role fax still plays in modern business.

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