A bull put spread is a vertical spread where you sell a put at a higher strike and buy a put at a lower strike, both expiring the same month.
Apple at $150:
Maximum profit: $3 per share ($300) if stock stays above $150. Maximum loss: $2 per share ($200) if stock falls below $145. Breakeven: $147 ($150 - $3 credit).
Maximum Profit: Credit collected
Maximum Loss: Width of strikes minus credit
Profitable Zone: Above the sold strike at expiration
Use when bullish or neutral. You profit from the stock staying flat or rising. Time decay works for you.
Related: Bear Put Spread, Bull Call Spread, Vertical Spread