Whichever approach you prefer, you can make iPhone Mail use it by default for text you quote in your replies and when forwarding.
Make iPhone Mail Indent Quoted Text in Replies and Forwards (or Not)
To set up iPhone Mail to indent quoted text when you reply or forward:
- Open the Settings app.
- Choose the Mail, Contacts, Calendars category.
- Now tap Increase Quote Level.
- Make sure ON is selected for Increase Quote Level.
- To include quoted text just set apart from your text with a header but not indented, make sure Increase Quote Level is OFF.
With Increase Quote Level enabled, iPhone Mail will indent quoted text with "> " in plain text and set it apart as a block quote in rich-text messages.
You can always increase or decrease the level of select text's indentation.
(Updated October 2011)