You may have heard some trainer or some commercial say something like “Turn fat into muscle!”. They just use these phrases to get to you, to make you think, “Wow maybe if I buy that I can turn my fat into muscle”. In reality fat and muscle are two completely different things in the body and serve completely different functions.
Fat stores energy for later consumption by the body.
Muscles contract and expand to aid in motor functions.
One cannot become the other.