The general app settings are a miscellaneous set of options for the To Do app.
Sound: Toggle on and off the "task completed" sound.
Folder order: Tap "Reset the sort order of folders" to return the folders to their original sort order. The folders will be sorted in order of creation date, from oldest to newest.
Tasks: Change whether new tasks are added to the top or the bottom of your lists.
You'll also find the app version listed here. New versions are automatically pushed to the app when you're connected to WiFi. This app version is unrelated to the version of the app shown in the App Store and Play Stores.
Lastly, the Uninstall button will uninstall Zenkit To Do from your Zenkit Suite. This will not uninstall the app from your device, but remove any lists you have set up.