How to copy and paste file with the "Remote Desktop" app?

There are two RDP clients for Windows 10:

• the old Remote Desktop Connection client (built-in)
• the newer Remote Desktop client (windows store).

While I have no trouble to copy and paste files around with the old client, I cannot manage to do the same thing with the newer client. How do I copy and paste files between machines with the Remote Desktop app?

According to Microsoft here, it is possible if you use version 10.1.1107 or later (09/04/2019):

You can now copy files between local and remote PCs.

According to Microsoft here, it used to be impossible. You could copy-paste text between sessions, but not files. Their proposed solution was using the old application, Microsoft Remote Desktop Connection.

As already pointed out, this functionality is not currently available in the 'Universal App' - this is, apparently, largely down to the Sandbox nature of Windows Universal Apps.

You can however C&P plain text - just not files & folders.

There is a full, official, comparison between the apps available here

You can use administrative share to access remote drive. From run menu 'Win key + R' enter \\<ComputerName>\<DiskVolumeName>$ where as “<ComputerName>” put the name of the computer with the Admin Shares enabled on it (e.g. “Computer01”) and as “<DiskVolumeName>” put the name of the volume that you want to access, (e.g. “C$” = Disk Volume C:\ , “D$” = Disk Volume D:\, etc.)

https://www.wintips.org/how-to-enable-admin-shares-windows-7/