In any editor, Cut, Copy, and paste are basic operations to copy the lines of a code.
There are multiple ways to Cut, Copy, and Paste in the VIM editor.
One way,
cut: press dd on the cursor line
copy: press yy on the current cursor line
paste:press p to the cursor where you want to paste. This paste the copied or deleted line after the cursor.
use P to paste the line before the cursor