Yes, you are correct. Some carriers may charge for SMS messages used to activate iCloud services or verify your Apple ID. When you set up or sign in to your Apple ID on a new device, Apple may send a verification code to your registered phone number via SMS. This verification code is used to confirm your identity and ensure the security of your account.
While Apple itself does not charge for these SMS messages, your carrier may apply standard text messaging rates or fees for receiving the verification code. It's important to be aware of any potential charges from your carrier, especially if you are in a region or on a plan where SMS messages incur costs.
If you're concerned about potential charges for iCloud activation or verification codes, you might consider using a Wi-Fi connection to complete the setup process, if possible, as this would not incur additional carrier charges for data usage.
Keep in mind that carrier policies and rates may vary, so it's a good idea to check with your specific carrier for information about SMS charges and any other related fees.