The candle itself has high and low. If we take Moving Average for example, it can be applied to these prices:
0_1548372524269_c2b6ebd5-e74a-4f0f-8aa7-2f50c50dfeb6-image.png
By default the applied price is Close, which means that you get MA of only the Close prices of the candles. You can try to set MA to 1, change the applied price and you will get the idea.
If you are asking about something, I'm not sure what it is...