How to remove restrictions from iCloud on iPhone?

Are you telling us that you are seeing a screen that says "Locked to Owner" – i.e., you have encountered Activation Lock?

If you are the owner who locked the phone, see

How to remove Activation Lock - Apple Support

if this is a second-hand phone and you have discovered that it is Activation Locked to someone else, see

The All Too Common SAD Reality of Buying a Used iPad/iPhone – Apple Community

If this is about your locked Apple Account, have a look at the troubleshooting in this article, to be able to use it again:

If your Apple Account is locked, not active, or disabled - Apple Support