customization
US /ˌkʌs.tə.məˈzeɪ.ʃən/
UK /ˌkʌs.tə.məˈzeɪ.ʃən/

1.
the action of modifying something to suit a particular individual or task
:
•
The software allows for extensive customization of the user interface.
•
The company offers various options for car customization.