To take part in the DPoS process, users save up digital assets to form a 'stake,' and delegate it to those who do all the upkeeping work and get a share of the reward in return. This process is called staking. By staking, you take part in the consensus mechanism.
Staking is a vital process for DPoS blockchains. It allows selecting the best block producers to do the work, ensures decentralization and minimizes the chances to ruin the network. Staking allows more block producers / validators to be involved in the blockchain, and more network users to collect rewards.