Open Outlook
Click New Email (or Reply/Forward)
Place the cursor in the email body
Click where the emoji should appear
Press Windows key + . (period) to open the emoji picker
Select an emoji to insert it
If using Outlook on the web, click the emoji icon (or press Windows key + .) in the message compose area and select an emoji
To insert an emoji via copy/paste, copy an emoji from any source and paste it into the email body
To use an emoji in Outlook on Mac, press Control + Command + Space, then select an emoji and insert it
Send the email after inserting the emoji