Welcome, Jake_de_corgi, to Apple Support Communities!
Whether images, documents, whatever are FORMATTED “as icons” or FORMATTED as “embedded”; regardless, they are ATTACHMENTS: always have been, always will be (barring a change in the MIME standards).
I have sent and received many emails, with various documents, both on Macs and iPads, using Apple Mail, and have never had any problems with any form of document!
I have also verified—using the definitive test [ found at Email photo as attachment, not embedded, … - Apple Community ]—that all Apple Mail included documents are sent as ATTACHMENTS, regardless how they may appear to be FORMATTED!
The only problems I have seen people report, so far, have been when reading any such emails using Outlook, or one of its derivatives.
I’m sorry if the FORMATTING is distracting, to you. I’m sure the intent is to facilitate access, for the recipients (so they can preview the PDF document before fully opening it).
Unfortunately, as we have seen with photos, some, long-not-updated email clients (like Outlook and its derivatives) do seem to have some troubles—and even downright misbehaviors—with some more advanced forms of MIME compliant email content, such as from Apple Mail.
Especially since the MIME standard even allows old email clients to ignore the optional “formatting” directives, such as those used by more modern email clients, such as Apple Mail, I don’t see why Outlook, and its derivatives, would be so problematic.
Unfortunately, until Outlook, and its derivatives, become fully MIME compliant, we will continue to have such issues. (Fortunately, such are a very tiny subset of email clients [in terms of how many programs/apps are involved, even though the market penetration of such poorly programmed apps seems to be disproportionately high].)
Please contact the developers of such problematics email clients, to have them bring their email clients “up to snuff”. (Hopefully sooner, rather than later.)
