The Highest High Value indicator plots the highest price reached in a specific number of periods. The default period is 14 but you can change that in the StockChartsACP platform.
The Highest High Value is plotted as an overlay on the price chart.
Since the Highest High Value represents the highest high observed over several periods, you could use it to make entry and exit decisions. For example, if price breaks through the upper band, it could indicate that price will continue moving higher if the Highest High Value continues to move higher. If the indicator flattens out and starts turning lower, it could indicate an overbought condition. This could be an alert to exit a long position.
To help determine an exit point, it helps to add the Lowest Low Value.