Where is the location of the file (pdf) exported by nextcloud office (CODE)?

I cannot find the pdf exported on my android phone.

The nextcloud server is using CODE backend for nextcloud office.
In the nextcloud app, I did the following steps:

  1. I open a file (New document.odt), type some random words in it
  2. Press hamburger menu → Download as → PDF Document (.pdf)
  3. In the android notification, the app “Download Manager” displayed “New dowument.pdf Download complete.”
  4. Now I can press this notification to open the file, but after I quit the file, I can no longer find it on my android phone
  5. Or I swipe out the android notification after download, I can no longer find it again. But when I download the file again, the notification say “New document(1).pdf Download complete.”, so it should be storing somewhere
  6. I used command find . -iname '*\.pdf' -type f -mmin -30 in termux but no result.