Support is a horizontal area on your chart where potential buying pressure could come in and push the price higher.
Resistance is a horizontal area on your charts where selling pressure could come in and push the price lower.
The more times support or resistance is tested within a short period of time, the greater the likelihood it will break.
Observing support and resistance is one way to identify an area of value on your charts. Others include looking at the moving average, trendline, channel, etc.
Support tends to break in a downtrend or when there are lower highs into support.
Resistance tends to break in an uptrend or when there are higher lows into resistance.
Source: Price Action Trading Secrets Book
Disclaimer: Below price chart shared for Educational purpose only, Not a recommendation to take the trade.