Price action is encompassed in technical and chart pattern analysis, which attempt to find order in the sometimes seemingly random movement of price.
It is a form of technical analysis and it uses candles on a chart which represents data. This data shows what the market has been doing for the specified time period. For instance, a daily candle shows what the market did for that day. All economic data and global news which affect price in any way will be reflected on the price chart so it eliminates almost any use of following the news.
Price action is readily observed in markets where liquidity and price volatility are highest, but anything that is bought or sold freely in a market will per se demonstrate price action.
Some examples of price action are swings (high and low), tests of resistance and consolidation.