Hi there and welcome
Some data still remains on the phone, as it still needs to run some internally, but the rest is moved to the SD card. you cannot change this.
If you delete the app from the phone, it removes all the data from the phone but then you cannot use the app until you install it again.
If you would like any additional information or assistance, please do not hesitate to let me know.
Else if you can take a second to rate my service by clicking one of the stars at the top of the screen then submit, that would be greatly appreciated.