Mime Mail

The name that all site emails will be from when using default engine.
The email address that all site e-mails will be from when using default engine.
Use the simple format of user@example.com for all recipient email addresses.
Gather all style sheets when no mail.css found in the default theme directory.
This option disables the use of email messages with graphics and styles. All messages will be converted to plain text.
This option disables the embedding of images. All image will be available as external content. This can make email messages much smaller.
This option disables the removing of class attributes from the message source. Useful for debugging the style of the message.
The filter set that will be applied to the message body. If you are using Mime Mail as default mail system, make sure to enable "Convert line breaks into HTML" and "Convert URLs into links" with a long enough maximum length for e.g. password reset URLs!