The MACD indicator from MetaTrader 4/ differs from similar indicators in other applications. This is a result of the fact that in the model of MetaTrader 4/, the MACD line is displayed as a histogram, whereas traditionally it is displayed as a line. additionally, in the version of MetaTrader 4/ , the signal line is constructed using SMA, whereas by definition it ought to be built using EMA. In the version of MetaTrader 4/5, the histogram can also be different (the difference between the MACD line and the signal line), this might be unusual for novices in using MetaTrader 4/5, since the MACD line itself is displayed as a histogram.
This indicator displays the MACD as it was conceived by the author (Gerald Appel), as it is shown in other programs. The MACD line is calculated as the difference between the fast and slow EMA. The signal line is the EMA from the MACD line. The MACD histogram represents the difference between the MACD line and the signal line (the MACD histogram itself can be used to get divergence signals).
The switches allow you to display / hide the MACD line, signal line, and histogram.