What is best app to manage storage?

I suggest starting by using the built-in apps that already come with your Mac's operating system.

Ref: How to free up storage space on your Mac - Apple Support

One note of caution. I strongly suggest that you avoid any third-party "cleaner" apps for this purpose. We get numerous posts here with folks asking for help to remove them as they caused more harm than good.

battcronin wrote:

I need to locate and remove clutter including files in the "Other" files. What is best app to manage storage on a MacBook Pro running MacOS Catalina?

from the Terminal.app, for details, copy and paste the command line:

sudo du -h -d 1 ~/

File size, and finding missing GB— list the items in the home folder with the sizes, including invisible items.

sudo du -h -d 1 /

File size, and finding missing GB —will list the items in root with the sizes, including invisible items.