I have to set up a shared mailbox on an iPhone. It is important to synchronize the part of contacts and calendar.
As I understand it, you can configure (mainly) the emails on IPhone in 2 ways:
Native application Allows you to add mailboxes shared by IMAP. Can't sync calendar / contacts
Outlook application Shared mailboxes can be added. Cannot sync contacts and / or calendar with native iPhone contacts and / or calendar. This is possible with Android, but not with IPhone and this is important to me.