To connect a Yahoo/AOL/CalDAV or subscribed calendar to the Calendars app, you first need to add the account to your device’s Apple Calendar settings.
- Go to Settings.
- Tap Apps > Calendar > Calendar Accounts.
- Tap Add Account > Choose the provider (for example, Yahoo or AOL).
- Follow the on-screen steps.
- Open System Settings.
- Go to Internet Accounts.
- Click Add Account and select the provider.
- Complete the setup.
Once the account is added to your device, it will automatically appear in the Display Local Calendars section of the Local Calendars settings in the Calendars app.