We are experiencing this same issue. Not sure what is going on. Note that Files does allow in-place editing of PDFs, so it should be possible. Probably a new Info.plist setting or similar.

Just had exactly this. Fixed it by changing the name of the account entry. It had been filled in automatically, and included numbers and other characters. When I just changed that to my name, the form was accepted.

I was able to get this working, though not optimally. It seems that the SWCollaborationMetadata does not like having the default options be nil. In that case, it simply does not appear in messages. The solution for me was to provide SWCollaborationShareOptions(optionsGroups: []). The downside is that the "options" label still appears, but shows a completely empty popover for the options :( At least it does now appear in messages, and does work when posted to others. If you are having trouble getting the invitation to appear in Messages, it is also worth checking the Settings/System Preferences, and in the Messages Preferences. There are various restrictions there on Shared with You, and if your app isn't allowed, they won't show up.