Explanation
In this case, the phishing e-mail lures a potential victim with a fake proforma order notice.
Instead of having to click on a link, the user is lured to open the attachment.
When opening it, the user is presented a fake login page, with the Adobe PDF logo at the top and a fake blurred invoice text in the background, where they have to enter their e-mail credentials in order to view the fake invoice.
Example