Daylio opens PDF or CSV in the wrong app
Android allows you to set different default applications for actions. In Daylio you can set an application for sharing content or exporting PDF/CSV or Backup File. We suggest using the storage apps like Dropbox, Google Drive, or email apps, so you can easily send your file anywhere.
If you somehow set up the wrong default app for any action you can always change it in the Android settings.
Go to Android Settings > Apps > "App name" and tap on the button CLEAR DEFAULTS. Remember you need to go to the app that is opening when you do the action (share, export), NOT Daylio.
Next time you click export it will ask you again to choose the app to open the file.