Well, let's start with what a QR code is. If you are too lazy to read in simple words, this is information encrypted into a picture. For example, you have a phone or tablet running on android or ios and in the app store you install a application for a QR code (for free). Applications for QR codes in modern phones are built-in by the factory. The camera in your device must be functioning.

Further, seeing the picture, some call them an alien, launch applications and scan it. After that, you will be shown information, such as address, phone number, website, and other.

You ask: "Why it is needed?", because you can simply write down or bookmark the site. I'll tell you simply, out of a hundred computer users, only ten percent are able to do this. And so he took the phone once and it's already there.

If you want to put a QR code on your website, it's very easy to do so. I liked the websiteplanet, write down your data, click generate and get a png image. Which you need to save and put on your site. It can also be printed if necessary.

There are many QR code generator sites, but remember that not many of them provide a direct link from your code. Usually they still cut them, through how profitable it is for them!