In December 2020, Ethereum set in motion its transition into a full Proof-of-Stake (PoS) network when it introduced a beacon chain. This is a PoS consensus layer whose purpose is to co-ordinate the network.
As a result, it became possible to stake $ETH to validate transactions, alongside a Proof-of-Work (PoW) mining.
Since then, there are generally two routes to stake $ETH and all depends on how much you are willing to stake. You’ll need 32 ETH to become a full validator, but you do not have to be a full validator to participate.