why not can create apple id ?

You have an Apple ID. You used it to sign into the Support community. Are you trying to create another Apple ID? That isn't recommended.

Maximum Free Accounts error message?

Create a new ID (if necessary) and sign into iCloud using the same Apple ID on another Apple device/computer. You should then be able to sign in.

The maximum number of free accounts have been activated

Apple ID - create a new.      

Apple ID – Create        

Apple ID - Could Not Create or Could Not Set Up iCloud message.    

Or contact Apple ID Support.  See the Apple Support articles below for contact information.  

Apple ID - Official Apple Support.    

Contact Apple for help with Apple ID account security - Apple Support.   (Link doesn’t always load)  

Get Support          Work through the screens to get a chat option. You may have to pick a slightly different problem.

Apple Support schedule phone call

https://twitter.com/AppleSupport.          People have posted it may take an hour or more to get a response.