If you copy or move an entire folder,
all of its contents, including
all subfolders, will also be copied or moved. Be aware that such
an operation can take a long time, depending on the number of bytes
that have to be physically copied between drives. However, moving
files between folders on the same drive is generally very fast
because the file system can usually just update directory information
instead of physically moving data.
Also make sure
that there is enough free space on the target drive to hold the entire
folder tree. You can use Treesize to find out
how much space an entire folder hierarchy takes.