The "MACD Crossing the zero level" indicator uses the DRAW_FILLING style to draw areas, in which MACD is above or below the zero line.

In the indicator settings, you can select the MACD line to show areas for, i.e. the main or the signal line:

Fig. 1. Displaying areas for the MACD signal line

Fig. 2. Displaying areas for the MACD main line