How to cancel the SMS synchronization between mobile phone and ipad?

1. Click Settings to find the avatar.

2. Slide down to find iCloud, where you can find various options for synchronous transmission. Just turn off the options that you don't want to synchronize. Manually turn off synchronization between SMS content and mobile application. When synchronization is turned off, the content on this device will not appear on other devices.

Extended data:

You can change the features you can use on any device by turning iCloud features on or off. You can also turn off iCloud completely.

After turning off the iCloud function on the device, you will not be able to use the information stored on iCloud on this device through this function.

If Mail, Contacts, Calendars, Memos, Reminders or iCloud Photos are turned off on only one device, you can still view and change your information on iCloud.com and other devices with this feature turned on.

In some cases, after turning off the iCloud feature on the device, you can choose to keep a copy of the feature information on the device. This copy of information will not be synchronized with iCloud.

If you close the mail, address book, calendar and tasks in iCloud(Windows Edition) on a Windows computer, the information stored in iCloud can still be used in Microsoft Outlook, but it will not be synchronized with other devices.

References:

Apple-iCloud: turn iCloud on or off.