For example, instead of sell TSLA put at 340 for $18 (this is a made up number), you can
Sell TSLA put at 340 for 18
Buy TSLA put at 320 for 10
In this bull put spread, you only get $8 credit, instead of $18 credit. But the benefit here is that you are protected if TSLA drop below 320 so you downside risk is protected.
So, you trade off the credit for more safety.