An XPS attachment is an XML Paper Specification document that has been attached to an email. An XPS document can be created with any Microsoft application, such as Word or Excel, and it can be viewed exactly as the document would look in its hard-copy form.
You can only view XPS documents with Microsoft's XPS viewer. This viewer is standard with Windows 7 and Vista. If you are sending the document to a person that's using an earlier version of Windows, such as Windows XP, he or she must download the viewer from Microsoft to view the document.
Microsoft says that XPS files are interchangeable among all of their programs. If you create the XPS document in a Microsoft program that the receiver does not have, that person should still be able to view the attachment by using any other Microsoft program.
XPS documents are not formatted for interaction. If you are sending a document to another user who will need to make changes, the XPS format is not a good option.