Toolbar button 'Return Receipt' adds in an easy way receipt request to composed message. After installing extension on the toolbar Compose window will be displayed 'Return Receipt' button. Now you can very quickly and easily add receipt request. Highlighted button informs that request is enabled.
Extension is available in 19 languages: Catalan, Czech, Chinese, Danish, Dutch, English, French, German, Italian, Japanese, Polish, Portuguese (Brazilian), Portuguese (Portugal), Russian, Serbian, Spanish (Spain), Swedish, Turkish, and Ukrainian.