Using LCD (ST7066U Controller) with PCF8574T Backpack

Wire.h comes with the Arduino.
You must install hd44780.h with the Library Manager.

There are so many "bad" LiquidCrystal_I2C versions that it is better to avoid them.
In fact your particular fmalpartida version should work ok when you diagnose the correct constructor (with the hd44780.h sketch).

David.