MACD oscillators consist of 2 lines: one directly to the MACD line (main line) and the signal line.
The main line, AKA MACD line, is calculated as follows: EMA with a period of 12 subtracted EMA with a period of 26.
The signal line is a moving average with a period of 9. An exponential or simple moving average is used as a signal line.
The intersection of the lines of the indicator is what gives signals to enter the market.