Rich Text for Mail allows you to format text in an iOS email.
The iOS Mail application is a great email viewer, but it really isn't that great of an email composer. It lacks a feature that many of us use in email every day - text formatting. Because of this, iOS developer Ryan Petrich
found it necessary to create a jailbreak tweak known as Rich Text for Mail
that allows you to change the formatting of your boring text in iOS Mail email composition. It's not a new tweak, but it's one that should be brought into the light