If the topic is closely similar or the same, can I use same supplemental essay for different colleges?
or they gonna find out.
On Common APP!!!
Yes, you can use the same essay for multiple schools.
Sure. Just make sure you tailor it a bit – generic supplemental essays aren’t the best way to get admitted.
Be sure you change the college name if it is mentioned in the essay!
My D used the same common app essay for all 12 of her apps. She chose the prompt saying “tell us something abou your identity without which you feel your application would be incomplete.” So there was no need to change anything for individual colleges. Several suppleental essays were reused, although modified a bit, to suit different supplemental essay questions at different colleges. There is no way for them to see that you have reused essays, they don’t have access to your applications to other colleges.
As mentioned ab pve, as long as you tailor it a bit, there is no issue reusing an essay. However, I would never suggest reusing a UChicago essay; they are too unique, and the AO’s will smell a retread from a mile away.
Retooling existing essays is standard practice.