How CFDs democratized trading
The contract for difference (CFD) allows you to trade the value of an asset. There is no need for you to own it. That is the key feature of online trading with CFDs. Because of that, you can profit no matter where the price of the asset is going. And this is what we call the democratization of online trading.
Remember that CFD trading, like any other type of investment, can be risky when an abrupt price change of a specific asset or leverage has been used.
The contracts for difference are something mostly offered on commodities, shares, synthetic derivatives, and indices. The CFD is an agreement for trading the difference in the value of a particular asset between opening the contract and closing the contract. You can sell/short and still potentially profit from a drop in the price of an asset.

Can you use CFD trading in forex?

A key thing in CFD trading: the spread
The spread is the difference between the asking price and bidding price when the opening of trade.
That is the commission a user must pay and depends on the size of the executed order. When the trade begins, it is at a minus balance because of the amount of the spread. If you click BUY, the indicated price is the BUY/ASK rate, but the price at which your position will open and trade will be the BID/SELL rate and vice-versa.