Hi,
Based on my konwledge, without the help of third-party applications, Exchange and Outlook itself cannot enable users to create/edit/delete shared calendars on the iPhone.
You could put forward your suggestions in Outlook UserVoice.. A large part of the prioritization of the new features and enhancements of Outlook by the Outlook team comes from users' votes and feedback in Outlook UserVoice.
In addition, according to a blog, iPhone can share calendars through iCloud and its own Calendar application, and can invite multiple people to view and edit calendar events.Hope it helps you: How to Share a Calendar from Your iPhone or iPad
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