Bull Call Spread means it is the position where one is thinking that Stock Market will move in upward direction and at the same time doesnot want to be greedy. What happens it is the prediction that Market be in upward trend but there is also probability that market could fall and the prediction will become wrong of going in upward direction. In order to avoid big losses, traders used to take small loss and Big profit.
Example: As on 2nd July 2023, Nifty Index is at 19189. So, I predict market will continue to move in upward direction. I want to have Small Loss and Big Profit. As a trader I purchased Nifty 27th July Expiry 19300 CE of one lot and I sold Nifty 27th July Expiry 19550 CE of one lot. By doing this my loss will be small and my profit will be big.