help with freeing up storage space and moving to external drive

If you're not using Lightroom Classic, then you must be using the Lightroom Desktop app. The local catalog for Lightroom Desktop is by default stored within the user's Pictures library on the main system drive, and that cannot be changed. However, any locally stored originals CAN be moved to an external drive, simply by changing the "Storage location for original files" at the bottom of the Preferences>Cache tab....use the "Browse" button to select a storage location on the external drive and Lightroom will automatically move any stored originals to the new location.