An asset's filename/URL is the actual filename of the asset. If a metadata title is already available on the asset, then the metadata title—not the filename—will display on the asset list.
Follow these steps to change a asset's filename/URL:
Navigate to the location of the asset that you want to change the filename.
Click on the Select option in the Action bar at the top.
Select the asset.
Click on Move option from the Action bar
In the Move configure panel Step 1, update Asset name after move field.
(Note: Name field cannot contain special characters except "-" and "_". Read more on best practices for URL nomenclature)
Click Next one more time to save the new Name.
If the asset filename does not appear to update after being renamed, it is because the asset's metadata title is visible rather than the new filename. Please see the FAQ page on How to change asset metadata title? for information on how to edit or delete the metadata title.