vCard is an old standard. It is a way to represent the contact information. It is a digital version of a business card.
When you receive a business card, you probably want to enter the data into your cell phone.
This is where the QR Code comes in.
QR Code is a way to get information into your phone. Nowadays, phones almost all have the camera capability. QR Code is a way to let you take a picture of the bar code and to scan the bar code into your phone. One image can contain a lot of information.
Combining QR Code and vCard allows you to pass the information from the business card to your phone, without manually typing those information.
How to create a business card QR code
6 Good Reasons to Add a QR Code to Your Business Card