I can’t use my i cloud account nd can’t chnge lock scree passcode

If an app or feature on your device is not working, not appearing, 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 support article If your Apple ID or other options are greyed out in Settings —> If your Apple ID is greyed out in Settings - 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.

How you reset a Screen Time passcode depends upon the system version you are using:

If you or a member of your Family Sharing group have a mobile device running iOS or iPad OS 13.4 or later, or a Mac running Catalina 10.15.4 or later:

Read this support article for instructions on what to do if you forgot your Screen Time passcode --> If you forgot your Screen Time passcode - Apple Support

If you still have issues resetting your Screen Time passcode, contact Apple Support.

Contact - Official Apple Support