I don't know iCloud ID and password but I am remove the iCloud possble
My phone iPhone 11 Pro Max but I don't know you iCloud ID and password can possible remove iCloud but I don't know iCloud ID name and old password
iPhone X, iOS 14
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The Apple ID can be found from the device that is in possession If you forgot your Apple ID email address or phone number - Apple Support
The Apple ID password can be reset If you forgot your Apple ID password - Apple Support
Once attained the account credentials , the Apple ID can be signed out Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac - Apple Support