The MACD indicator is a trend-following dynamic indicator which indicates the correlation between two Moving Averages of a price.
The Moving Average Convergence/Divergence - abbreviated as MACD - Technical Indicator is the difference between a 26-period and 12-period exponential moving averages (EMA). For showing clear opportunities, a so-called signal line (9-period moving average of the indicator) is plotted on the MACD chart.
The MACD is most effective in wide-swinging markets. There exist three popular types for using the Moving Average Convergence/Divergence: crossovers, overbought/oversold conditions and divergences.
You can download the MACD indicator here: https://www.mql5.com/en/code/35