If spelling is not your "trump card", professional emails really bother you. No one wants to send misspelled emails, so allow Microsoft Outlook to automatically check emails before sending them.
The best way to fix spelling mistakes in an email is not to do it first, and that's why Outlook can help you help. The Microsoft Outlook client has a setting that forces the spell checker to Happen after clicking the "Send" button. If no errors are found, the email is sent as usual; if a spelling error is detected, Outlook gives you the option to correct it before sending the message.
To enable this setting, open the Outlook desktop application and click File> Options.
In the Mail> Compose Messages section, do switching in the “Always check spelling before sending” check box.
Click "OK" in the lower right corner to save and close the "Options" panel.
Settings completed. Now, when we click "Send" to an email with a spelling mistake, Microsoft Outlook will locate and will give us the opportunity to change it.
If you find something in the email that the spell checker did not find and you want to change it, do so click in the "Cancel" option.
This will open a dialog box that allows you to cancel sending the email. Click "No" to prevent the email from being sent.
Source of information: howtogeek.com