Fax apps are downloadable applications that are designed to allow smartphones to simulate some level of fax machine functionality. Some of these apps can send and receive faxes, while others are only capable of viewing them. Another option that is sometimes present in a fax app is the ability to fill in certain data fields with the smartphone keyboard, or even sign documents. It is also sometimes possible to use a smartphone camera to take a picture of a document and then send that file as a fax. In some cases, a fax app may simply provide a connection to a paid Internet fax service, though others are purely based on cellular infrastructure.
Facsimile, or fax, technology has been an important aspect of business communications since the 1970s. This technology has traditionally involved connecting a fax machine to a phone line, and then using it to call another phone line that is also connected to a fax machine. The fax machine that initiates the call can then scan and transmit a document over the phone connection, after which the receiving machine will reproduce it. This can be used to transmit all different types of documents, though it is particularly useful for obtaining signatures remotely.
Smartphones are capable of voice and email communications, but typically lack some of the most important functionality offered by fax machines. Since many professionals rely on these devices for business communications, the fax app is one way to add that missing functionality. Different fax apps have a variety of feature sets, though the ability to receive and view faxes, typically through an Internet connection, is the one commonality. Some of these apps require a subscription to an Internet-based fax service, though that is not always the case.
In addition to receiving and viewing faxed documents, it is also sometimes possible for a fax app to create and send new documents. Some apps require the user to email documents to a service so that they can be reformatted for faxing, while others are capable of sending any file as a fax. Another way that some fax apps function involves the use of the built-in camera present in most smartphones. This type of fax app allows the user to take a picture of any document, and then send it as a fax. Some of these apps also allow the user to sign his or her name into fax documents, since that has traditionally been such an important use of fax technology.