If you’re using Office 365 or another Exchange-based client, you can also restore deleted items using Outlook Web App. For more information, see Recover deleted messages or items in Outlook Web App.
If you don’t see Recover Deleted Items, you’re probably not using an Exchange account or you don’t have a folder selected in that account.
Tip To select multiple items, press Ctrl as you click each item, and then click Recover Selected Items
Recovered items are restored to the folder you’re working in.
Note Your Exchange administrator specifies the retention time for deleted items. After this time elapses, deleted items can’t be restored.
For more detailed instructions, please visit Microsoft's Support page for Recovering deleted items in Outlook.