Why directory name is not recognized from Terminal window, but is recognized from my MacBook Air desktop?

Do you have a case-sensitive file system? Your folder is named HideIt but you asked Terminal to change to Hideit.

From Desktop as the working folder, try typing Hi then tab key. It should expand out the full name of the folder. When it does, try entering the command.

Try:

ls | cat -vte

This will make any invisible characters visible, display tabs, and put a $ at the end of the string.

I suspect you have a leading or trailing space in the name.

spaces in file names and folders.

If you are going to be working from the command line a lot, then when you are naming a file or folder, just use _ (Underscore) where you would put a space, and your life in the command line will be easier.

Where you do not have control, or should not change a name macOS created, then you either single quote, double quote or backslash quote the name

Folder greg

would be specified on the command line as one of the following:

"Folder greg"
'Folder greg'
Folder\ greg

You can drag and drop a file or folder from the Finder to the Terminal window, and it will be properly quoted for use.

Copying a directory

cp -rp /path/to/directory/to/be/copied  /path/to/parent/directory/

So if I have a directory $HOME/Downloads/Fred and I want to make a copy in the parent directory $HOME/Documents, I would enter:

 cp -Rp  $HOME/Downloads/Fred  $HOME/Documents/

OR

cd $HOME/Downloads
cp -Rp Fred  $HOME/Documents/

Or

cd $HOME/Documents
cp -Rp $HOME/Downloads/Fred  ./

The -R will is for recursive and it will make sure all subdirectories under Fred are copied as well.

The -p is so that file permissions are preserved.