Import key from ios11 Files
Import key from new Files feature. I use my iPad often without a computer around so needing to connect to iTunes to import it not going to work for import
We are sorry for the inconvenience.
Termius has this feature but unfortunately it’s broken in current release. We’ll fix it with the next update.
For now you may use a workaround:
In Files app select the key file and press “share” button (the one that has the icon of a square and arrow, should be at the bottom-left corner) and press “Copy” in the sharing menu. Now you should be able to paste it in Termius in the New Key screen.
Here is the video example I’ve recorded for you:
Hope it helps
You can't import the key from iTunes anyway if you have iOS11. I can't connect at all because of this lack of capability in Termius.