Essentially some people make proposals, meaning they request specific changes to be made to the protocol and the community and delegates vote on whether they agree or not. If the proposal is accepted then the changes will be implemented.
When a proposal has been submitted to the Inverse Dao, you can find the vote here
To be eligible to vote, you either need to already have done one of two things:
Delegate your INV vote to another delegate (someone else)
You can delegate your voting power to yourself on the delegate page