Those categories within the macOS Storage Management section refers to anything on the Mac which is considered an app regardless of their location. macOS includes some "apps" within the system areas, plus any macOS executable you may have downloaded or stored on the laptop in the home user folder will be part of this as well.
You either need to delete large files/folders that you don't need, or relocate the large files/folders to external media. Look through your Desktop, Documents, and especially Downloads folders. And don't forget to empty the Trash.
If your Photos, Music, and/or iMovie libraries are large, then you can relocate those large libraries to an external drive:
Move your Photos library to save space on your Mac - Apple Support
Change where your music files are stored on Mac - Apple Support
Move your iMovie for Mac library - Apple Support
Keep in mind that it may take 24-48 hours before you will see the Free storage space increase after deleting or moving large amounts of data. Ignore the "Available" storage value as it is extremely misleading and is not synonymous with Free.