To change the text encoding:
Choose Message > Text Encoding, then choose the text encoding you want, or "Automatic" if you want Direct Mail to decide.
Text encodings determine how special or international characters are transmitted over the Internet. By default, Direct Mail will automatically choose a text encoding that preserves special or international characters. If you want to override this choice, you can set the text encoding manually.
Choose Message > Text Encoding, then choose the text encoding you want, or "Automatic" if you want Direct Mail to decide.