Bull Flags are one of the most well known & easily recognized chart patterns.
The most important factor in identifying any flag pattern is the clear "staff" or "flagpole"; there should be a straight run upwards leading up to the pattern or it is not a valid pattern.
After the straight run upward price starts to Zig Zag between two converging trendlines forming a tight wedge (it can be slanted, or even symmetrical) until the price "breaks out" above the upper trendline signifying a possible continuation in trend upwards.
Bull Flags have the highest success rate out of any pattern and work extremely well when paired with long term support & resistance areas. Enter at the invalidation point of the pattern (A), second entry on the bullish retest (B). Pennants that are “tighter” have higher success rates, look for patterns forming on top of long term resistances (not below) to increase probability of success also. Pattern height is measured and added to swing low before breakout for possible target.
Sometimes large size traders can generate liquidity by faking out under the pattern support as we can see on some of the examples. The liquidity generated by triggering stop losses underneath the pattern can fill large position sizes for whales and is a good indicator for a long position once the price confirms support back inside the pattern.