Why does iPhone 6 keep sending text messages automatically?

It may be that the mobile phone is infected with the IOS SMS virus. The characteristic of this virus is that it sends text messages by itself. It is recommended to restore the phone to factory settings.

Steps to restore factory settings on an Apple phone:

Enter the settings interface and click General in the settings interface;

After entering the General interface, click Restore;

After entering the restoration page, click the Restore All Settings option.