I want to know why my Apple ID is restricted please?

What is the exact error message? iCloud does not have a "restricted" status. If you mean a disabled account, the support article If your Apple ID is locked or disabled - Apple Support has solutions for two frequently encountered reasons for an account to be disabled/locked:

● If the message says "your account has been disabled in the App Store and iTunes Store" or "locked" then you must contact Apple; you cannot resolve this yourself. Apple provides a link for this specific issue. Tap or click here --> https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362 .

● If your account has been disabled for security reasons the solution is to reset your password as outlined in this document: If you forgot your Apple ID password - Apple Support

If you are unsuccessful you may need to request account recovery as outlined in this document How to use account recovery when you can’t reset your Apple ID password - Apple Support , or additional assistance from Apple Security: Contact Apple for help with Apple ID account security - Apple Support

If it's another reason then post here with details.

If an app or feature on your device is not working or is restricted (grayed out), it may have been disabled using Screen Time, or by an IT administrator if you are using a device owned by an employer or educational institution.

- Read this document about using Screen Time on an iPhone, iPad, or iPod touch --> Use Screen Time on your iPhone, iPad, or iPod touch - Apple Support

Tap Settings > Screen Time > Content & Privacy > scroll to Allow Changes.

- If the device is managed (Settings > General > VPN & Device Management), contact the IT department that is doing the managing.