Change Email Format in Outlook for Windows
It’s easy to change the format of your Outlook email, whether it’s just for one message, replying to or forwarding a message, or if you want to set a default email format.
Change Email Format When Replying to or Forwarding a Message
Change Email Format for One New Message
Change Default Email Format for Sending Messages
To set a default email format:
How to Use HTML or Plain Text Formats in Outlook.com
If you use the Outlook.com webmail service, select either HTML or Plain Text from the Outlook.com settings.
How to Change the Message Format in Outlook for Mac
Set individual messages to use HTML or plain text formatting in Outlook for the Mac when composing an email message:
Choose Format > Make Plain Text (available only when the current format is rich text).Choose Format > Make Rich Text (available only when the current format is plain text).
To use the same format for all messages, go to Mail > Preferences, select Composing, then choose a message format. If you want to use a different format for replies, select Use the same message format as the original message.