How does the enzyme ATP Synthase work and how exactly does it makes a molecule of ATP?

ATP synthase is a complex which makes use of the proton potential created by the operation of the electron transport chain in mitochondria. It transports a proton down the gradient and uses the energy to complete the phosphorylation of ADP to ATP.

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.