To "copy" hold down your mouse key and run the cursor over the passage you want to copy.  Once it is highlighted, hold down the CTRL key (located at the bottom of your keyboard) and with the CTRL key down push the "C" key. This copies your highlighted selection onto the "clipboard".

To "paste" the passage to a new email, simply put your cursor on the email page where you want the passage to go and hold down the CTRL key again, then push the "V" key to paste.  This should paste what you had copied onto the clipboard into your e-mail where you put your cursor.   This works between all programs in Windows.