>my forms's date format is dd-mm-yyyy (set date italian dmy)
>Now, I want to show it in report as yyyy-mm-dd (in string format )
>How can I save the date format form dd-mm-yyyy into string format (yyyy-mm-dd)

?TRANSFORM(DTOS(DATE()),"@R 9999-99-99")

if you don't want to change your SET DATE setting.