I learned something today: Any mail client on iOS that supports being the default mail client may not support all of the features of the Apple Mail client.
I've tried other default email clients on iOS and I've deleted the Apple Mail app. When I go to a contact in the Phone app and press the "Mail" button when the contact has a valid email address, I will get a dialog box asking if I want to download and install the Apple Mail app. I did not know that that dialog box is a function of the new default mail app not supporting that feature!
I've downloaded, installed and configured Preside. It supports creating a new message from the Phone app's Mail button.
I've tried other default email clients on iOS and I've deleted the Apple Mail app. When I go to a contact in the Phone app and press the "Mail" button when the contact has a valid email address, I will get a dialog box asking if I want to download and install the Apple Mail app. I did not know that that dialog box is a function of the new default mail app not supporting that feature!
I've downloaded, installed and configured Preside. It supports creating a new message from the Phone app's Mail button.