Importing, Culling and Permanently Deleting (all forms of photo(s)/files both in Lightroom and Disk

3. Simply how can you fully delete a photo in Lightroom. EVERY part/type of the photo.  Nothing left, anywhere.  I realize deleted items would be sent to 'Trash', expected, but no part of the photo anywhere else in Lightroom or disk. 

By @Christopher273132298foz

There are many, many wrinkles to the question you’re asking, so if the answers you get are not what you’re looking for, you may need to be more specific about what problem you’re running into.

Basically:

• If you want to delete the original photo and you’re viewing a folder, you can just press the Delete key and confirm it. 
• If you want to delete the original photo and you’re viewing a collection (virtual list), pressing the Delete key normally deletes it from the collection without deleting the original, so to delete the original while in a collection, press Command-Option-Shift-Delete. 
• If you are tired of seeing the “move to trash?” confirmation alert and just want to delete without any further steps, the same Command-Option-Shift-Delete shortcut bypasses the confirmation alert, so use that shortcut with caution. 

If you want to delete the original photo and all of its derivatives, when you delete an original photo:

• All virtual copies of it are also deleted, and all copies synced to the cloud from Lightroom Classic are deleted from the cloud. All copies synced through Publish Collections are probably also deleted on next sync. 
• All instances of the photo in collections are deleted, including slide shows, print layouts, books… 
• Previews might be deleted automatically; if not immediately, then the next time previews are scheduled to be purged (like if “After One Week” is selected in Catalog Settings, File Handling). 

As in any application, deleting an original photo does not automatically also delete all copies of it that you made with the Export command, so… 

• If an exported copy is in any catalog, you will need to open that catalog and track it down manually for deletion; for example, using a filename search inside a catalog if the filename still matches the original. 
• If an exported copy is not in any catalog, you will need to track it down manually in macOS for deletion; for example, using a filename search on the Mac desktop if the filename still matches the original. 

Not hard at all. 

1. https://helpx.adobe.com/lightroom-classic/how-to/import-photos.html

2. (and more) https://helpx.adobe.com/lightroom-classic/help/photos.html

You WILL have to manually empty the trash, LR doesn't control this part of the process, the macOS does.