Privacy coins are unique cryptocurrencies that allow a user to gain total anonymity when making blockchain transactions. The identity of users and the origins of their transactions are completely protected.These coins empower senders and receivers to remain anonymous with different levels of privacy, like hidden wallet addresses and transaction balances. With privacy coins, payments actually remain private.
Monero (XMR) and ZCash (ZEC) are some of the most well-known cryptocurrencies with anonymity functions.
Source: https://medium.com/shapeshift-stories/what-are-privacy-coins-6df8622ebf76#:~:text=Privacy%20coins%20are%20unique,their%20transactions%20are%20completely%20protected.