copy

COPY  -  copy the current message into another mail file

Usage:  COPY [/type] filename  
  Unless specified, /type is "mbox".

Please note that COPY acts on the "current message" in your mailfile, and 
  -NOT- on the message you have just written.  If you are REPLYing, the
  "current message" is the one you are replying to.  To save the message 
  you are writing, see help for SAVE-DRAFT or FCC.

The COPY command copies the message to another mail file, and also leaves 
  it in the current mail file (compare to MOVE).  

If the mail file named exists, COPY adds a copy of the message to the end 
  of the file.  If the mail file does not exist, COPY creates it, unless
  the variable auto-create-files is set to NO.  If a directory is not 
  specified with the filename, COPY assumes the MAIL-DIRECTORY, which by 
  default is your home directory. 
  
If a type is not specified, /mbox is used for new files and the existing
  type is retained for existing files.  Use the type /mbox unless you also 
  use another mail system that needs another format.  /babyl and /mtxt 
  are the other types. 

Example:               
    Send>copy oldmail                #copies to a file named oldmail

For more help type "help" and one of these topics:
  move   headers   set auto-create-files   set mail-directory