TextNow is provided as an app for Windows and Mac OS X operating systems. You can download it from the TextNow website by choosing the appropriate link. It redirects you to either the Microsoft Store or Mac App Store for download.
In addition to these two desktop operating systems, you can install TextNow on iPhone, iPad, Android, Kindle, Nook and Windows Phone devices.
As of July 2015, the TextNow service provides free text messages to anyone in the United States and Canada. You can send text messages and voice calls to other TextNow users anywhere. The service does not require registration, and a TextNow phone number (US only) is provided to the individual user. In general, the reviews of the app and service are favorable. Additionally, the app provides for the sending of pictures, voicemail, call forwarding, signatures, emoticons, customizable ringtones and backgrounds, and text messages are synchronized between the computer and phone app.
As with all applications, there are sometimes issues with programming bugs and updates. For someone outside the US and Canada, it may not add much compared to Skype and Viber, for example. The other party in the conversation has to use the same application in any case. In North America, the text service does set it apart from other free messaging applications.