The term stands for Decentralized Autonomous Organization. A DAO is an organization represented by rules encoded as a computer program that is transparent, controlled by the organization members and not influenced by a central government.
You can vote on the official Snapshot page.
Improvement Proposals (BIPs), are the main form of governance. They are written proposals made by a team or community member proposals that are made to signal or effect change to its governance or products, they are posted on the forum and their main objective is to engage discussion with the community and look for its approval.
Follow the template on the Forum and simply post it. Once the proposal has been discussed for three days. It will reach community consensus and proceed to the next step of community snapshot proposal vote.