As you type, Outlook is already checking Spelling and Grammar behind the scenes. You’ve probably already seen the nice red, wavy underline under words that Outlook doesn’t recognize.
From any new item, choose Tools: Spelling and Grammar… from the Menu bar
Figure 37. Spelling and Grammar Dialog Box
2. For each error, choose Change, Change All or Ignore, Ignore All
3. When complete, click Close
Checking Spelling & Grammar Using the Shortcut Menu
Right-click any word with a red, wavy underline
Choose a spelling correction from the Shortcut menu