With Contract for Difference Brokers, sell trades can be placed( This involves borrowing a certain amount of currency from the broker and selling at a specific price).
This way, if the trades goes in the bearish direction, you make a profit and pay the broker their "spread".

How do you make profit from selling at a lower price?

You borrow BTC @ $34k and sell it @ $32k, where's the profit coming in from?