
Click on it and select " Other Email Address.". Then the " From" selection button will be shown.

A new message form will appear in the reading pane. Click new New mail above the folder list.Log in to your mailbox using Outlook Web App.On user given Delegate permission to send messages on your behalf, do the following procedures: (For Outlook Web App) You are recommended to tick the option " Automatically send a message to delegate summarizing these permissions" as well. Choose " Editor" from the list of Permissions for the Inbox.Select a user from the global address list, click " Add", and click " OK".Click " Account Settings" -> "Delegate Access".For additional permissions to the calendar and Mailbox are administered from the full Outlook client and cannot be controlled through OWA.

You can grant permissions for mailbox or calendar. The current version of Outlook Web App will not let you delegate permissions for other colleagues to view your Mailbox. You can set up delegate permissions so that someone can send messages on your behalf. Microsoft Outlook allows one user to send mail on behalf of another user.
