Voting is the twin process of editing, and while often neglected it is equally important for the correct functioning of MusicBrainz. User review and style guidelines are what makes the MusicBrainz data be relatively free of wrong information.
If you registered as a MusicBrainz user more than two weeks ago and at least 10 of your edits have been accepted, you can participate in the voting process. A good start would be to subscribe to a few artists and labels you're familiar with. By doing this you will receive a mail every day any other user enters any edits involving your subscriptions, and you'll also be able to access said edits via the Edits for Subscribed Entities link in the My Data menu on the site.
The act of voting is pretty simple: just choose Yes or No and enter your vote (you can also abstain if you're not sure). You should follow the Code of Conduct and, of course, you should not vote on a whim. Before voting on an edit, read all its edit notes: they'll usually let you know why the user is trying to make an edit. If the edit note is unclear (or there isn't one) feel free to (politely!) ask the editor for more information with your own edit note. You should also be familiar with the appropriate style guidelines and, if possible, with the entity being edited. If you're voting No, please always leave an edit note explaining why: this allows the editor to explain his reasons or, if the edit is just wrong, gives him/her pointers on what to do instead.
Voting is not always an one-off process. By default you will get an email when someone adds an edit note to an edit you've voted Yes or No on (or left an edit note on); these notes might sometimes convince you to change your vote. Or, if you stop being sure about your vote, just change it to Abstain.
The immense majority of edits stay open for 7 days unless they are approved by an auto-editor, in which case they are automatically applied, or get three unanimous votes before that, in which case they'll be either applied (3 Yes) or rejected (3 No) shortly. At the end of the 7 day period, if they're still open, a check is made. If there are at least as many No votes as Yes votes, the edit is rejected. If there are no No votes, or fewer No votes than Yes votes, the edit is applied.
This flowchart illustrates how edits become (or don't become) applied:
|Introductory guides||Beginners Guide · How to Create an Account · Introduction to Editing · Introduction to Voting · How to Write Edit Notes|
|Basic How-Tos||How to Add an Artist · How to Add Relationships · How to Use the Relationship Editor · How to Add a Release · How to Use Works|
|Specific How-Tos||How to Merge Releases · How to Add Cover Art · How to Identify Labels · How to Split Artists · How to Use Artist Credits · How to Add Standalone Recordings · How to Add Disc IDs · How to work with AcoustIDs · How to Tag Files With Picard|