Snapshot, a spinoff of Balancer, is an off-chain gasless multi-governance client with easy to verify and hard to contest results.
Snapshot derives its name from taking a "snapshot" of the Ethereum blockchain at a certain block number before voting opens. By having a fixed point in time, this eliminates the need to worry about moving tokens voting multiple times or someone using a flash loan to borrow a ton of voting power.
In order to be eligible to vote on Balancer proposals, you need satisfy at least one of the following:
Hold BAL tokens
Hold BPT tokens for pools that have BAL in them
Have someone delegate their voting power to your address
When a vote opens, click on the proposal in the Balancer Space, scroll to the voting section, and cast your vote. Your wallet provider will ask you to sign a message (don't worry, you won't be charged any gas).
If you're interested in learning more or want to use Snapshot for your own project, check out their documentation!