Start the signature line on the fourth line below Sincerely.  Type  or  stamp  the  following  infor- mation: (1)   name   of   signer   in   all   capital letters,  (2)  military  grade  (if  any)  spelled  out, (3)  functional  title,  and  (4)  By  direction  of  the Commanding  Officer  if  the  individual  usually signs  by  direction.  The  by-direction  line  may  be omitted on a routine business letter that neither makes a commitment nor takes an official stand. Women’s  names  may  begin  with  Miss, Mrs., or Ms. in parentheses. ADDRESSING  ENVELOPES 1.  General.  This  section  explains  how  to address   letter-size   envelopes   for   unclassified correspondence.  Ask  at  your  mail  room  about types,  costs,  and  instructions  on  such  special services   as   registered   mail.   Also   ask   about bulk  mailing  as  well  as  pouch  and  messenger services; these methods of moving the mail require few  envelopes  or  mailing  labels. 2.  Envelopes.  To  avoid  the  extra  charge  for mailing large envelopes, fold correspondence and send  it  in  letter-size  envelopes.  When  you  have several pieces of correspondence for one address, try  to  send  it  all  in  a  single  large  envelope. To   prevent   tearing   your   correspondence   or jamming  postal  equipment,  use  envelopes  only slightly larger than their contents and press out the   air   before   sealing   them.   Correct   minor errors   in   an   address   instead   of   discarding the envelope. 3. Addresses. Start an address halfway down the envelope and a third of the way from the left. Place  the  address  parallel  to  the  long  sides. Type,  stamp,  machine-print,  or  hand-print  the address. Use only black or dark blue ink. When using a rubber stamp, avoid smudging the address or  leaving  marks  from  the  stamp’s  edges.  Show your  return  address  in  the  upper  left  corner  of the  envelope. 4.  ZIP  Code.  Put  a  ZIP  Code  or  FPO/APO number   on   all   addresses.   On   1   July   1984   a ZIP  +  4  became  the  standard  code  for  all Department   of   Defense   (DOD)   components. ZIP  +  4  is  composed  of  the  current  five-digit ZIP Code plus a four-digit add-on. The additional four   digits   are   separated   from   the   existing five-digit  code  by  a  hyphen.  The  first  two  of these  digits  identify  broad  geographic  areas within  ZIP  Code  zones.  The  last  two  digits represent   the   smallest   geographic   unit   to which  mechanized  mail  distribution  can  be  made. For   more   detailed   information   on   ZIP   +   4 refer to OPNAVINST 5218.8,  Implementation  of the  Nine  Digit  ZIP  Code  System  (ZIP  +  4). 5.  State  Abbreviations.  The  two-letter  ab- breviations  must  be  used  on  envelopes.  They may be used in letters wherever a state appears as  part  of  an  address. PERSONNEL  MATTERS 1. Identifying Military Personnel. If positive identification  is  essential,  fully  identify  the member  when  you  first  mention  him  or  her. That  identification  often  appears  in  the  subject block of a standard letter or the first paragraph of  a  business  letter.  In  later  references  to  the member,  simply  use  the  rank  or  rate  and  last name. a.  For  full  identification  of  Navy  person- nel,  use  (1)  abbreviated  rank  or  rate,  (2)  first name,  middle  initial  if  any,  and  last  name, (3) branch of service, (4) Social Security number, and  (5)  designator  for  an  officer. Example: CAPT Robert W. Dole, USN, 123-45-6789/1110 b. For full identification of Marine Corps personnel, use (1) unabbreviated grade, (2) first name,  middle  initial  if  any,  and  last  name, (3)   Social   Security   number   without   hyphens, (4)  military  occupational  specialty,  and  (5)  branch of  service. Example: Captain Matthew T. Johnson 123 45 6789/0430 USMC. 2. Limits on Using Social Security Numbers. When  corresponding  with  DOD,  do  not  use  the Social  Security  number  of  a  military  member or civilian employee unless essential for identifi- cation.  When  corresponding  outside  DOD,  don’t use  the  Social  Security  number  of  a  military member or civilian employee at all, except if the individual  involved  gives  permission  or  the incoming  communication  already  shows  the  Social Security  number. 3.  Writing  to  Higher  Authority a. Navy Personnel. Prepare your letter on plain   bond   paper   in   standard-letter   format 10-20