It is not possible to send an attachment to a list via email marketing in Online Express. However, a link to the attachment made available can be included in your Online Express email blast:
  1. Upload the attachment to your website, or provide the attachment to your webmaster to do so. Test the link/file path to the attachment by opening it directly in a web browser to make sure the document is "public" and not behind an intranet / internal web environment. (NOTE: Please contact the appropriate software vendor or IT professional for assistance with this process or issue which is beyond Blackbaud's scope of support.)
  2. Insert the link/file path to the attachment in your Online Express email blast. For more information on designing emails, please refer to this Youtube video on Online Express email design.

Tip: Most emails are opened on mobile phones. So while it is possible to link an attachment using this technique, it may not be the most optimal channel. Instead of linking the attachment directly, another idea is to make it available via a web link on your site on a page related to the email information. Use the email marketing link to drive the traffic to your site, and then make the attachment link available there.