The preference is for Capitalised Case concatenated strings to delineate word breaks, although in order of preference, underscores and then hyphens are acceptable.
Please use logical folder names and only agreed and documented acronyms if necessary. The combination of folder and filename length is restricted to 260 characters. So please keep folder name lengths short particularly if you have a deep structure. Recommend folder name length is 30 characters. Removing spaces and not using underscores will save you some characters. Other characters such as / ? < > \ : * | " ^ are also strongly discouraged from use.
Where folders are determined that its contents should always be copied or moved to GA’s Records and Document Management System, it is recommended that the Container ID be added to the folder name (see example below). Do not rename folders in AWS environments, the recommend solution if absolutely necessary, is to create a new folder and move the data into it. Upon completion of the move, delete the old folder.