Rename Files & Folders

Hi,
I see ways to rename either files or folders; or to input files and then input folders and after that rename them all. But I am wondering if there is a way to simply rename all files and subfolders in one folder w/o the need to add files and folders separately. I would like to add them all in one go.
Can that be done, pls?
Many thanks in advance for any kind help!
Best,
:)
K