Basically iPod Touch was designed as a portable media player, personal digital assistant, and Wi-Fi mobile platform. The product was launched by Apple Inc. on September 5, 2007, at an event called The Beat Goes On.
As described above, the default functionality of iPod Touch does not have phone call, sms texting capability. However, hackers are always looking for a way to make this product able to do phone call, sms texting, voice mail and others just like a phone functionality.
Here is below one of guidances I found in Youtube how to turn iPod Touch into an iPhone functionality: