If you play lower rated players, your accuracy will automatically increase, because your opponent is making it easier for you to find the best move in the position (by blundering etc).
Other than that chess.com simply compares your move to a depth restricted, pre-AI version of Stockfish (AI requires a lot of computing time).
does accuracy depend on your rating like if a 2000 rated player plays the move i am making will his accuracy be lower like does different engines calculate the accuracy for different ratings?