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Step 1 - In the Outlook desktop app, select 'New Email'
Step 2 - Use the 'From' drop-down menu to select 'Other Email Address...'
Step 3 - Click the 'From...' option to expand the next menu
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Step 4 - Click the drop-down arrow to select 'Global Address List'
Step 5 - Type the name of the Shared Exchange Mailbox in the Search bar
Step 6 - Select the Shared Exchange Mailbox you want to add, then click 'OK'
Step 7 - Click 'OK'
Step 8 - The name of the Shared Exchange Mailbox will now be available when composing a New Email message in Outlook
