Is there a way to sign in to an iCloud to a phone that you do not remember the passcode on and change it so that you can login on it or you can get into it
iPhone 15, iOS 18
No it's not. The passcode on an iPhone is fully encrypted on the phone itself. If you don't remember or know the passcode on the phone, it cannot be changed from another device. The only way back into an iPhone in which you've forgotten the passcode is to use a computer with iTunes (Windows) or Finder (Mac) and erase the phone. Once reset, assuming you have a backup, you can restore the backup back to the phone. If you don't have a backup, your data will be gone.
See what you need to do here --> If you forgot your iPhone passcode or your iPhone is disabled - Apple Support
No it's not. The passcode on an iPhone is fully encrypted on the phone itself. If you don't remember or know the passcode on the phone, it cannot be changed from another device. The only way back into an iPhone in which you've forgotten the passcode is to use a computer with iTunes (Windows) or Finder (Mac) and erase the phone. Once reset, assuming you have a backup, you can restore the backup back to the phone. If you don't have a backup, your data will be gone.
See what you need to do here --> If you forgot your iPhone passcode or your iPhone is disabled - Apple Support
Changing the passcode on a different iPhone by logging in to the iCloud on another iPhone
