Office 365 (Outlook 2013) - Check spelling before sending a message
Important: By February 28, 2017, Office 2013 version Office 365 ProPlus is no longer available for installation with an Office 365 subscription. Microsoft will no longer push any updates to Office 2013 suite of applications - complete details.
To keep the Spelling & Grammar command always within reach, you can add it to the Quick Access Toolbar
If you don't want to do check spelling manually for every message---or you're worried you might forget!---you can set Outlook to check spelling for you every time.
- Click File > Options > Mail.
- Under Compose messages, check the Always check spelling before sending box.
Now when you click Send, Outlook checks spelling automatically. If there are no spelling mistakes, it sends the message right away. If you change your mind and want to edit the message some more, click Cancel to stop the spell check, and then click No.