The 'Outgoing Mail Width' option allows you to customize the width of the text box displaying messages for all the outgoing mail.
Click the 'Outgoing Mail Width' drop-down box to select the width in pixels of all the outgoing messages and click the 'Update Information' button. You have choices ranging from 60 to 130 pixels wide. If you select 70 pixels the messages you send people will be formatted in such a way that it is only 70 pixels wide. The recipient of the message will have the message displayed within a width of 70 pixels. You also have the option of not wrapping the text to a fixed width. This will display the entire message you receive in a single line without any restriction on its width.