icloud-where is my original document stored

iCloud Drive is a folder on your MacBook Pro.

You can see the iCloud Drive folder in Finder as I previously described. If you use Get Info for one of those files it will show the location as iCloud Drive.

The file itself is in 2 locations. The iCloud Drive folder on your Mac and on iCloud. (Speculation here but that may be why Apple chose to obscure the physical location a bit -- since they are synced between 2 locations.)

The physical location of the folder is a bit obscured. You can use the Finder "Go" menu, hold down the option key and click Library and then click the Mobile Documents folder in Library.

If you still are in any doubt (and I suspect you are), turn off your wi-fi or discontent the ethernet connection to your router. Then use the Finder sidebar and access your files. They will all still be there.

There will be a local copy on your MacBook Pro unless 1) you turned on Apple menu > System Preferences > iCloud > iCloud Drive - Options > Optimize Mac Storage and 2) your Mac is low on storage space.

I should add that there is also a copy of your files on iCloud (off your Mac). Any change (edit or deletion) to either two copies are automatically synced. You can use a computer browser (e.g., Safari) and log in to www.icloud.com and go to iCloud Drive there to directly access the copy on iCloud.

According to your screenshot, you do not have Optimize Mac Storage turned on. Therefore you definitely have a local copy (on your Mac) of all of your iCloud Drive files.

Because you turned on the "Desktops and Documents" option of iCloud Drive, your Documents folder has been relocated from its normal location. It is now in your iCloud Drive folder on your Mac. You can access your iCloud Drive folder by clicking on it in the Finder sidebar or by using the Finder "Go" menu.

Also, selecting or de-selecing the Optimize Mac Storage option would make no difference in your case. Since your local drive is only 1/3 full there would be no need for the system to optimize your files (i.e., no need to remove any local copies).