Daylio opens CSV in a wrong app
We suggest using the storage apps like Dropbox, Google Drive or email apps, so you can easily send PDF or CSV file anywhere.
If you somehow set up a wrong default app for opening PDF/CSV file you can always change it in the Android settings. Just go to Android Settings > Apps > "App name" and tap on the button CLEAR DEFAULTS. Remember you need to go the app that is opening the PDF/CSV files, not Daylio.
Next time you click export it will ask you again to choose the app to open the file.