How to prevent SMS sharing between iPhone?

This is because information synchronization in iCloud is turned on. The solution is to turn off information synchronization in iCloud. The specific steps are as follows:

First turn on the phone, find "Settings" on the phone desktop, and click Enter.

Second, after entering the settings, find the top column of "Apple ID, iCloud, iTunes, App Store" and click Enter.

3. After entering Apple ID, iCloud, iTunes and App Store, find the "iCloud" item and click Enter.

Fourth, after entering iCloud, find the "information" column and close it to solve this problem.