I'm not sure exactly what you are wanting to do, but look here:


to change the information displayed on the top-left corner of the invoice
  • in the admin section go to Configuration>My Store
  • then edit the Store Address and Phone fields.

to change the image on the top-right corner of the invoice,
  1. Replace the image <zc-home>admin/images/logo.gif with another image of the same name and dimension OR
  2. Adjust the following settings in the <zc-home>/admin/includes/languages/english.php file to suit the dimensions and name of your custom image
  • define ("HEADER_LOGO_WIDTH', '200px');
  • define (HEADER_LOGO_HEIGHT', '70px');
  • define (HEADER_LOGO_IMAGE', 'logo.gif');
(source: e-Start Your Web Store by Goh Koon Hoek)

I hope that answers your questions!