The page is available only for System Administrator of TM and gives the ability to define and configure the mailboxes for the TM System over the TM-FE without access to TM Configurator. The mailboxes will be used for specific workflows and features.
The mailboxes should be created and configured on Exchange, before defining them in the TM System.
To navigate to Mailboxes, user should open left side menu and choose the 'Mailboxes' page. Mailboxes page has two tables with a list of Credentials and Mailboxes:

Mailboxes page

Edit option is available for each Credential or Mailbox on the edit pop-up. User should choose a particular item in the list and click 'Edit' button to make changes .
Delete option is available for each Credential or Mailbox as well. User should choose a particular item in the list and click 'Remove' button .