ETH holders can activate validator software by staking at least 32 ETH. By doing this, they take on the role of a validator and assume responsibilities surrounding data storage, transaction processing, and adding blocks to the blockchain. The validators contribute to Ethereum's security, all while earning additional ETH as rewards.
Why Stake ETH?
Rewards are earned by validators who contribute to the network's consensus by processing transactions into blocks and verifying the work of other validators.
The network gets stronger against attacks as more ETH is staked, as it then requires more ETH to control a majority of the network.
Stakers don't need to do energy-intensive proof-of-work computations to participate in securing the network meaning staking nodes can run on relatively modest hardware using very little energy.