Process of Including library on Arduino IDE software
1. First of all open your browser
( example :- google chrome / safari /opera mini / mozilla firefox / etc.)

2. Next type in search bar which library you want
( example :- servo motor library for arduino / lcd i2c display library for arduino / oled library for arduino / etc.)

3. Next click on this ( image shown below )

4. Next click on this and download the library ( video shown below )
5. how to install library on arduino IDE ( video shown below )