FaxFile is a free app that works with both iOS and Android devices, and allows you to send PDF, doc/docx, and photo files to fax numbers in the U.S. and in Canada.

There isn’t a monthly subscription cost, but you do need to buy fax credits. Credits are available through either the app store for iOS or the Google Play store for Android. Credit purchases range from $2.99 (for 50 credits) to $49.99 (2,000 credits). A typical fax is 10 credits per page, so if you’re planning to send a high volume of faxes it makes sense to buy more credits at once to save money.

Installing FaxFile is easy – just find it in your phone’s app store, install, and you’re ready to go. To send a fax, make sure you have enough credits (you can purchase them directly from the app), then hit the icon that says “send fax.” You’ll be prompted to select files and add recipients. To add photos, either browse your existing photos or take a new photo and add it to the queue. For documents, open the app that’s home to the document (for instance, Dropbox or Drive) and use the “open in” command to send a copy of the document to FaxFile.

You can either add recipients from your contact list, or enter a fax number directly. Should the fax fail, FaxFile automatically retries without charging you extra credits.

FaxFile will also let you add a cover page, although you may have to install FaxCover, which is also free.

And that’s it – your fax should be on its way, all from your mobile device. FaxFile wins points for its ease of use and good transmission quality. However, it’s not the cheapest way to send faxes from a mobile device. If you fax regularly on the go, you might get a better deal by using an online fax service that includes a smartphone app.