This is Library for LCD-I2C module. This module features a PCF8574 chip (for I2C communication) and a potentiometer to adjust the LED backlight. The advantage of an I2C LCD is that the wiring is very simple. You only need two data pins to control the LCD. for reference you can visit https://www.dfrobot.com/product-135.html
Create a new folder called "LiquidCrystal_I2C" under the folder named "libraries" in your Arduino sketchbook folder. Create the folder "libraries" in case it does not exist yet. Place all the files in the "LiquidCrystal_I2C" folder.
To use the library in your own sketch, select it from Sketch > Import Library.
This library is based on work done by DFROBOT (www.dfrobot.com).