Where does body fat go when one loses weight? how does it leave the body? is it exhaled? urinated out?

When you take in fewer calories than your body needs, your body turns to fat reserves for energy. The byproducts of fat metabolism leave your body as water through your skin when you sweat and your kidneys when you urinate, and as carbon dioxide through your lungs when you breathe. ref: https://health.clevelandclinic.org/where-does-body-fat-go-when-you-lose-weight/

It is not an object or a thing. Fat is used up as energy and like any other, the waste product in the body its waste is got rid of in stool and urine , the two most common ways of excretion.