How can I move my PDF files listed in the Acrobat app from the iPad storage to Adobe Document Cloud? I use Acrobat on my iPad to read PDFs. They are currently stored on the iPad. How can I move all my PDF files from the iPad storage to Adobe Document Cloud?
Note that:

I can't transfer multiple files+folders at once from the Acrobat app on iPadOS 13 or 14 directly to my computer, which runs Windows 7.

The following screenshot shows some action that can only be applied to 1 PDF file at a time. However, I am looking for a solution to upload all my PDFs at once to Adobe Document Cloud, since I have a few hundreds of them.
Safari 
You can upload all files at the same time using Safari on your iPad.

Open Safari and visit https://documentcloud.adobe.com
Sign in and press the upload icon
Select Browse... and navigate to &quot;On my iPad&quot; (located in root) then Adobe.
Select the three dots icon (...) and choose the Select option.
Select all files you would like to upload and press open.

Files app 
You can e-mail or export all files at the same time using the Files app.

Open Files app
Navigate to &quot;On my iPad&quot; -&gt; Adobe
Select all files you would like to export. You can select multiple items from the three period menu (...).
Use share icon and select preferred exporting method.