When you access your Office 365 Outlook Web App http://outlook.office365.com (more commonly known as OWA) you will not have access to your shared mailbox folders by default and need to add these to your OWA profile.
To add the shared mailbox so it displays under your primary mailbox in Outlook Web App follow the below steps.
This method is recommended if you want to monitor the email from your primary mailbox and the shared mailbox at the same time. In addition, after you complete this task, the shared mailbox and its folders are displayed in the left navigation pane each time you open Outlook Web App.
– Sign in to your account in Outlook Web App.
– Right-click your primary mailbox in the left navigation pane, and then choose add shared folder. * Top tip – you may need to click on the ‘more’ button to expand your mailbox!
– In the add shared folder dialog box, type the name or email address of the shared mailbox, and then click add.
The shared mailbox displays in your Folder list in Outlook Web App. You can expand or collapse the shared mailbox folders as you can with your primary mailbox. You also can remove the shared mailbox from your Folder list.
– To remove it, right-click the shared mailbox, and then click delete.
To send email from the shared mailbox using Outlook Web App:
– Click new mail above the folder list. A new message form opens in the reading pane.
– Click the more options icon ( … ) and then select ‘Show From’. This option shows you that the people who receive the email message will see that it comes from the shared mailbox and not from your own email account. Simply type the address you wish the email to be sent as. NB you must have the ‘send as’ permission to be able to do this. If you do not please contact your Office 365 system administrator. The first time you enter the address Outlook Web App searches for that address. In the future, the name is cached so it resolves quickly.
– Complete the email and then send as normal.