How to access file through WebDAV?

I enabled the WebDAV extension.

I have a password manager app that needs to access a file (database) on my seafile server.

It can use DAV and gives me a dialouge to fill File URL, username, password:

What should be the url of the file if the file is located at My Libraries/libraryName/path/to/file.kdbx and the server is located at sf.example.com ?

Have You followed the instructions provided here: https://manual.seafile.com/extension/webdav.html?

If you’re on Android you can use the content:// URIs provided by the seafile app. This is discussed more thoroughly on this thread

Yes I did.

Check out Nextcloud documentation: https://docs.nextcloud.com/server/9/user_manual/files/access_webdav.html

To access your Nextcloud files using the Dolphin file manager in KDE, use the webdav:// protocol:

webdav://example.com/nextcloud/remote.php/dav/files/USERNAME/

They clearly gave what the file path would be.

From Seafile documentation all I cloud make out was https://example.com/seafdav then what comes next in the url? User name? Then the library name?

https://example.com/seafdav/library_name/path/to/file

Exactly. In all clients I know username and passphrase need to be provided separately.

https://username:password@example.com/seafdav/library_name/path/to/file

that should also be valid, depending on your client, though not recommended.