Volume is as important as the price action itself, and can even be more helpful than any chart pattern or technical indicator.
Volume is used as a confirmation to various signals and a leading indicator on price action.
Volume is the total value of an asset bought or sold within a trading session or candle. If the candle closes negative, the volume will appear red. If the candle closes positive, the corresponding volume bar will be green.
Rising and falling volume can say a lot about the strength of a trend. When volume is rising rapidly, it signals that the price action is attracting more participants and interest in trading is growing.
When volume is falling, it is often a signal a trend is waning and a reversal could be near. That reversal is usually confirmed with a breakout in volume. If the reversal happens before a confirmation of volume, there is risk of a false breakout.