No Option to Respond to Calendar Invitations on iPhone

I’m experiencing an issue with my @iCloud.com email and calendar on my iPhone.

The issue has two parts:

Part 1: Receiving Calendar Invitations as Emails Instead of In-App Notifications

According to Apple’s support documentation, iCloud Calendar allows users to specify how they receive invitations—either as in-app notifications or via email. My settings are configured to receive invitations as in-app notifications.

However, when I receive calendar invitations from non-iCloud services (e.g., Google Calendar via Gmail or Microsoft Outlook via an Outlook email address), they arrive as emails in the Mail app with the invitation attached as a .ICS file. I do not receive an in-app notification in the Apple Calendar app as expected.

After researching, I found that many users report the same issue. It appears that invitations from external calendar services default to email-based delivery rather than following the iCloud preference to send in-app notifications.

Part 2: No Option to Respond to Invitations on iPhone

When I open the email and tap the .ICS file, I can select "Add to Calendar," choose an iCloud calendar, and tap "Done" to add the event. However, the event is marked as "tentative" (displayed with grey diagonal lines).

The problem is that once the event is added, I have no option to officially respond (e.g., "Accept," "Maybe," or "Decline") within the Calendar app on my iPhone. The only available action is "Delete Event."

The only way I can respond and send a reply to the sender is by using my MacBook Pro. If I don’t have access to my laptop, I have no way to send my response from my iPhone.