We don't store your data, period.
We don't use any third party services that could have access to your data.
All data is private to the application; if you delete it, you delete your data.
The only way for the data to leave your phone is if you decide to share the data using share button. We have no control who do you share the data with, so make sure you trust however you're shareing your data with.
Use the form on home page.