To enable/disable Backup & Sync:
- Open the SwiftKey app from your device
- Tap 'Account'
- Tap 'Backup & Sync'
- Check/uncheck Backup & Sync
Please note that disabling Backup & Sync will not automatically remove your SwiftKey Account data. If you would like to clear your data, you will need to do this separately. For information on how to do so, please see the article, How do I clear my learned language data?.