An indent string is a standard sequence of characters that you specify. It appears to the left of each line of text of a forwarded message, or message text that you include when you reply.
For example, if you specify the string: ``> '', your included text would look like this:
> This is the text > of the included mail message.If you type responses to the original message, they are visually set off from the included text by the absence of the indent string, making your responses easy to read. For example:
> This is the text > of the included mail message.
This is my comment on the original message.
To specify an indent string, select Message from the Preferences menu, click in the ``Indent String'' field, and type the text of the string.