You can move a file to another folder or even another Department by selecting 'Move File(s)' from the 'Dots' menu on a file, like this...
You can even move multiple files at the same time by simply selecting select multiple files at once, as follows:-
Select one file in the Library, hold down the shift key and select any other files you want to apply your changes to. Still holding down Shift, click the 'dots' menu on one of the files then choose 'Move File(s)', which prompt you to select a new destination folder, then moves all the files in your selection at the same time.
This same principle can also be used for changing File Access & Privileges, applying File Metadata, Changing file Ownership, setting the 'Lifetime' of a file and even Removing File)s), so please be careful how you use it!