How do I adjust my new account login on my iphone

See -> -If you see a Could Not Create Apple ID or Could Not Set Up iCloud message

If you see a Could Not Create Apple ID or Could Not Set Up iCloud message - Apple Support

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If you still need to set up iCloud with this Apple ID, contact Apple Support for help. 

Your Apple ID is the account you use to access Apple services like the App Store, Apple Music, iCloud, iMessage, FaceTime, and more. You sign in to all Apple services with this single Apple ID and password.

BTW: You are sign in here .  .  .  with your Apple ID & Password (?).

Your Apple ID is the personal account you use with all Apple products and services. It includes the email address and password you use to sign in, as well as the contact, payment, and security details that you use with Apple.

You can’t merge multiple Apple ID accounts.

What happens if you use the Apple ID that you use to sign in here?

Check your Apple ID via your email box, see this Apple article: If you forgot your Apple ID

If you forgot your Apple ID email address or phone number - Apple Support                  

OR see -> Having trouble signing in?

https://iforgot.apple.com/password/verify/appleid

See -> If you can't connect or sign in to iCloud

If you can't connect or sign in to iCloud - Apple Support

See this Apple article: If you forgot your Apple ID password

If you forgot your Apple ID password - Apple Support

Then see this Apple article: What to do after you change your Apple ID or password

What to do after you change your Apple ID or password - Apple Support

You can also contact Apple support for help, -> Get Support (apple.com)

You have to show proof of ownership of your product, provide all documentation showing your purchase of the device.

If you do not have additional proof of ownership, contact the reseller. They may be able to provide the original purchase document.

Once Apple receive your proof of ownership, Apple will further review your request and provide an update.

Using the new ID, sign into iCloud using the same Apple ID on another Apple device/computer. You should then be able to sign in.

If you see a Could Not Create Apple ID or Could Not Set Up iCloud message.  *

The maximum number of free accounts have been activated    -

Apple ID - create a new.      *

Apple ID – Create       -

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.  -

Apple on Twitter