With the rapid development of Information and communication technologies and the widespread use of the Internet and smartphones, the QR codes (stands for quick response code) are becoming a promising tool for connecting offline and online services. This article is the first in a series of two articles that aim to contextualize the use of QR codes in health education. This will allow the educators to develop the skills necessary for its creation and use in medical education. Successful implementation of the QR Code in health education requires a knowledge of certain basic information about both the QR Code itself and the necessary requirements for the use of this type of symbology. This first article presents an overview of the current state of the art of the QR codes and discusses in brief the structure, symbology, versions, properties and the requirements for the use of this type of symbology. In the second part of this series we will describe the main aspects related to: custom QR Code with Logo, static and dynamic codes, and the different tools and applications necessary to generate and decode a QR code as well as how to apply it in different educational contexts of Augmented Reality. The final purpose of these two articles is to ensure that all educators feel familiar with this technology and can incorporate it into the educational material used in the teaching-learning process, both traditional classroom and online courses.