I've never seen anyone do that until yesterday. So I wanted to know is this appropriate for when preparing apples for any meal, how about other fruits? Unlike plates, fruits can absorb chemicals.
No, you would not use a detergent or soap when washing fruit.
Normally, you would just wash them with water, using a brush on thick skinned produce.
See, for example, Best Ways to Wash Fruits and Vegetables from the University of Maine extension.