iPads are not a true laptop replacement.
AND, unless you purchased a 128 or 256 GBs iPad Pro, you may not get every file from your PC onto your iPad Pro.
There is no file system present on iDevices and iOS.
If you want to organise images/photos into folders that you can name anything you want and even create sub folders, look at these iOS apps.
I have been using the first app since it became available over 5 years, ago.
Photo-Sort for iPad by Romain HENRY
https://appsto.re/us/E98bw.i
The above app creates duplicate images to organise into folders and sub folders and you can pick the order in which you want images to initially download into folders.
So, if you do not want two sets of images on your iPad, you can delete the ones from your Photos app camera roll.
If you ever want to return an image/photo back to the Photos App camera roll, HD Photo Sort can do that, as well.
Easy Photo Sorter - Organize photos with your favorite conditions. by Canon Marketing Japan Inc.
https://appsto.re/us/h8c4-.i
Pics 2 by Phyar Studio
https://appsto.re/us/7EhPY.i
MyPics - A Powerful Photo Viewer, Editor and Manager by Takuto Nishioka
https://appsto.re/us/RFOfE.i
Good Luck!