Cryptocurrencies use Proof of Work and Proof of Stake, two distinct consensus techniques, to approve transactions and add new blocks to the block chain.
Proof of work is used by Bitcoin, Dash, Bitcoin Cash, Dogecoin, Zcash, and other cryptocurrencies.
Proof of Stake is used by Cardano, Polkadot, Binance Coin, Avalanche, VeChain, and other cryptocurrencies.
It is important to note that some cryptocurrencies use a hybrid consensus mechanism that combines elements of both PoW and PoS.
If you want to know about proof of work and proof of stake, then check out the below video for more information -