Moving photos of a smart collection (coming from several LR folders) to another LR folder

How can I do that? (ignoring the advice above )

1) Select (highlight) all the photos you see in a Smart Collection (or even multiple selected Smart Collections)

2) Drag the photos (start with cursor on a photo, not a border) to a destination folder. Or [Right-Click] a Folder and [Move Selected Photos....]

If  the 'Destination' folder does not show in the Folder panel (it would need one imported photo) you can create a new folder-

To move the files to a new folder-

1) As above- Select photos.

2) [Right-Click] on a 'parent' folder in the Folder panel

3) Choose [Create Folder Inside  "parent folder"...]

4) Name the new folder, Check the option [Include selected photos]

[Create] -Done.

Note: By moving photos from imported folder to another folder, you are really messing with your folder structure -as in advice from @dj_paige 

You might be better using Export methods to create 'copies' to show clients, etc, or make Standard Collections from the Smart Collections and Sync the Std Collection photos to the Cloud for Sharing to clients by the Web.

Here's my opinion, and I will point out in advance that there may be a lot of people who don't agree, that's fine, you can think about what I say and decide for yourself if you agree with me or not. By the way, I have seen plenty of people agree with me too.

I think the whole idea of re-organizing folders is sub-optimal, since Lightroom Classic gives you far superior tools to obtain good organization. These tools are keywords and other metadata, like captions, titles, GPS locations, etc. So, my advice is to leave your photos where they are, do not move them to new folders (later today or tomorrow or whenever you take new photos, you can import those into folders named by capture date). Instead of spending time moving photos around from one folder to another, spend that time adding keywords and other metadata, with the intention of using keywords and other metadata to do all your searching. You will wind up with a far superior organization than anything you can do via moving photos from one folder to another.

I have no idea what folders my photos are in, other than the parent folder is on my D:\ drive and is called "Nikon Photos". Lightroom Classic knows what folders the photos are in, so I don't have to. When I want to find photos of waterfalls, this is easy when I search for that specific keyword, I don't have to know what folders these photos are in, and furthermore, these photos can be in dozens of different folders, I don't know, but I can find them in a few seconds.

Last comment: I said "I think the whole idea of re-organizing folders is sub-optimal, since Lightroom Classic gives you far superior tools to obtain good organization", there is one exception. If you want all your photos on one drive and perhaps inside a single parent folder, then you can do those moves, moving entire folders to the new drive and location; so instead of wherever the folders are now, you could move them to be subfolders under a single parent folder. (I still don't recommend moving individual photos in this exception; move entire folders.) You can do these folder moves in Lightroom Classic, or you can do it in your operating system and then re-connect Lightroom Classic to the new location of the folders via these instructions.