From the home screen, tap Settings.
Scroll to and tap iCloud.
To activate iCloud Tab Syncing, tap and drag the Safari toggle to the right.
If prompted to merge Safari data with iCloud, tap the preferred option.
Safari tabs will now sync with iCloud.
To disable tabs syncing, tap and drag the Safari toggle to the left.
If prompted, tap the desired option. (e.g. Delete from My iPhone)
iCloud Tab syncing is now disabled.