All users that will be sending out signature requests will need to authorize the HelloSign for Confluence Plugin. You can authorize the plugin on your profile under the Settings tab. This allows the plugin to make signature requests on your behalf. The Authorize menu takes you to HelloSign's sign in page and associates your account once you log in. This requires at least a HelloSign Silver Tier subscription with API Signature Requests and OAuth tied to the account.
You can revoke HelloSign for Confluence's access by simply clicking the Revoke button that is seen in Figure 1.