Helpful Tips For Sending Faxes with eFax

With eFax®, you can send faxes conveniently in several ways: by email, website, mobile app, or eFax Messenger®. As always, no fax machine is required.
Please refer to the guidelines below to ensure successful delivery and quick processing of your sent faxes. 


Fax Attachments

  • For all send methods (Email, Mobile App, Web, , eFax® Messenger), the maximum number of attachments is 10. The total file size is 20 MB. Use the Large File Sharing feature to send files up to 3 GB (aggregate) to up to 20 people.
  • When using either the Send a Fax web form or when faxing by email, files are transmitted in the order they are attached. When faxing from the Mobile App, files are also transmitted in the order they are attached; however, you may rearrange the file order before sending the fax.
  • Attached files must be supported file types.
  • Attached files must use standard Windows fonts.
  • Attached documents should not have password protection or macros enabled.
  • There must be no hyperlinks/live element components in the file(s).


File Names

  • Keep file names under 21 characters, including the file extension. File names should be alpha-numeric only with no spaces.
  • Do not use symbols in the file name (e.g., @, %, *, $, ^, ~, (), #, !, &, +, =, etc.). Underscores (_) and dashes (-) in the name are acceptable as long as there are no spaces. Periods should only be used to separate the file name from the file extension.


Faxing Photos and Scanned Documents

  • We recommend using the eFax Mobile App (instead of email or the Send a Fax form) for sending photos or scanned photos as it has been optimized for this purpose.
  • Documents should be scanned in black and white only (never color or Greyscale). Scanning at 200 DPI (dots per inch) is preferred, though 300 DPI is acceptable.


Cover Pages

  • If you want to use your own cover page when sending faxes using the Send a Fax form, uncheck the Include Cover Page option. Be sure to attach your cover page to the outgoing fax as the first separate file.


Formatting Fax Numbers

  • When sending faxes using the Send a Fax form, be sure to remove all formatting from the Number field. For example, 1-202-555-1234 should be entered as 12025551234.
  • Do not include local or international dialing prefixes; the country code selected in the Country drop-down field provides the correct dialing format. For example, to send a fax to the UK number (0) 20 7555 1234, select UK (44) from the Select Fax To Country list and type 2075551234 in the Fax Number box.


Sending Faxes by Email

  • Remember that to send by email, you must first register your email address to send faxes. To do so, go to Account Preferences > Send Email Addresses and add your email address to the list. You may register a maximum of 5 email addresses to send.
  • When sending faxes by email, remove all number formatting in the To: field. For example:
    • To send to the US fax number +1 323 555 1234, type [email protected], where 1 equals the Country Code, 323 the Area Code, and 5551234 equals the fax number.
    • To send to the UK number +44 (0)20 7555 1234, type [email protected], where 44 equals the Country Code, 207 the Area Code, and 5551234 equals the fax number. Do not include the “0” before the fax number.
    • To send to a NGN (non-geographical number) in the UK/EU, you will need to enter the recipient’s fax number followed by in the To: field (instead of using Note: Sending to these number types is more expensive. For information on send rates, click here.