Organization when moving from one drive to another

You don't say that you are using Lightroom Classic, you said you are using Lightroom. I assume you are using Lightroom Classic and not Lightroom. Please confirm.

Before you do this, you need to make backuips of everything, catalog file and photos. But of course, I assume you are doing that regularly anyway.

Migrating photos does not require migrating the catalog. The catalog can remain on the original disk, if you wish.

To copy photos to another disk, use your operating system, copy the photos (not move the photos) to the second disk. Do not go into the folders and change anything like moving photos to a different folder, do not change the folder hierarchy, do not change folder or file name. Straight copy, nothing else. Then re-connect your Lightroom Classic catalog to the new location by following these instructions (particularly Figure 4 and associated text). https://www.computer-darkroom.com/lr2_find_folder/find-folder.htm

Once you are convinced that everything is working with photos on the second disk, you can (optionally) delete the photos from the first disk.

Please describe your computer system. Mac or PC? Internal or external drives? What size of drives are you working with? How many photos do you have referenced in the Lightroom Classic catalog?

The basic means of assuring your photos and edits make the move from one drive to another is to have all your image folders under one Main "Photos" folders. The name doesn't matter, but it should be easy to recognize. If you aren't organized in that way, you can do it in Lightroom Classic before moving the photos to another drive. By moving, I mean copying the entire image file structure to the new drive in the exact same organizational system. After "Copying" the images to the new drive, you must verify that they all got copied and backed up properly before removing them from the original drive.