how to transfer folders from pc to ipad

Yes, there should be no issues at all. This is one of the benefits of iCloud Drive. Now, on your PC, create the folders you need under iCloud Drive and move the files to the folders.

Now the question is: do you want those files on you iPad only, i.e. the "On My iPad" location when you browse the Files app? If yes, you'll need to create a new folder structure on your iPad matching the one you seek and move the files to their respective folders. Once those files are on your iPad "only", you can remove them from iCloud Drive.

That might not be possible.

Folders of what? And which iPad do you have?

~Lyssa