Hello mainerone,
Welcome to Apple Support Communities. We're glad you're here and thank you for your post.
We understand from your comments that the shared calendar details are missing after you deleted a few apps on your iPhone. We'll be glad to share some tips to help you.
"Several things happen when you restore an earlier version of your calendars.
Your sharing settings get erased. You can share the calendars again, or you can ask the owner to share them again.
iCloud cancels and recreates all of your upcoming, scheduled events, then resends the invitations for you."
To restore your missing calendars:
- Sign in to iCloud.com.
- Click Account Settings.
- Scroll down to the bottom of the page. Under Advanced, click Restore Calendars and Reminders.
- Click Restore next to the date before you deleted your calendars.
- Click Restore again to confirm. After the restore completes, you'll get a notification on iCloud.com and an email to the address on file with your Apple ID."
We trust these links and tips will help you find the missing calendar so you can enjoy the rest of your weekend.
Kind regards.