Just copy the ESP8266 QRcode folder to your Arduino 'libraries' folder. I have included an example sketch.

The code is based on qrdquino by tz1: https://github.com/tz1/qrduino And https://github.com/anunpanya/ESP8266_QRcode

Open Library Manager (menu Sketch > Include Library > Manage Libraries…) then install the following libraries

• Mini Grafx by Daniel Eichborn, Fabrice Weinberg

• Open Arduino IDE, try examples of MiniGrafx QRcode library