Follow these steps.
- Click File at the top left of your screen.
- Click Options in the left column.
- Click Mail in the left column.
- Under the Compose Messages heading, click the Spelling and Autocorrect button.
- Under the heading “When correcting spelling in Outlook,” check the box next to “Check spelling as you type.”
- Click OK to save your changes and close the Editor Options window.
- Click OK to close the Outlook Options window.