You need access to your apple account associated with the iCloud Calendar you want to connect.
You need to obtain your unique app-specific password from Apple.
Check if writer's access is required:
If you want to add events created in the system to your iCloud Calendar, writer's access is necessary for the calendar.
If you simply want to fetch all your events from your iCloud Calendar to the system, read-only access will suffice.
Step 1: Obtain your unique app-specific password from Apple
Before connecting your iCloud calendar, you'll need to obtain your app-specific password from Apple. This unique password is distinct from your regular Apple account password. Apple mandates the use of an app-specific password, in addition to enabling two-factor authentication, when connecting to third-party applications.
To obtain your app-specific password, follow these steps:
1. Sign in to https://appleid.apple.com/
2. Enable two-factor authentication under the Security section if you haven't already done so.

3. In the App-Specific Passwords section, choose 'Generate Password.'


4. Enter a label for the password (for instance, 'CRM iCloud Integration') and click 'Create.'

5. Copy and safely keep the generated app-specific password. This will be used when connecting your iCloud calendar in the next step.
