This dialog allows you to publish the document in the workflow process. You can either approve or reject documents.
Approve
When you approve the document, it is moved to the next workflow step.
Reject
When you reject the document, it is moved back to the previous workflow step.
Permissions
In order to be allowed to approve or reject document, you need to have Modify permissions for it and you need to be a member of one of the roles that are allowed to approve/reject documents in this workflow step. Or you need the "Manage Workflow" permission which is usually granted only to administrators.
E-mails and comments
You can choose to send an e-mail with your comment.
When you approve the document, the e-mail is sent to all people who are allowed to approve the document in the next step.
When you reject the document, the e-mail is sent to the user who last approved the document (in the last step).
Even if you do not choose to send an e-mail, the comment is saved to the workflow history that is displayed at the bottom of the page.
Special workflow steps - Edit and Published
There are two special (default) workflow steps:
Edit - this step is always the first one and allows all users with modify permission to update the document. It's also the first step after creating a new document. Any user with modify permission can approve the document and send it to the next workflow step.
Published - this step is always the last one and it means that the latest version of the document has been approved and is published now. You cannot approve or reject the document in this step. If you have modify permission, you can check out the document and edit it which automatically moves the document to the Edit step.
See also: Workflow and Versioning Overview, Check in, Check out, Document History