code for printing a banner

 im sending an email where im printing a banner in case of non prod db hence i added a placeholder in the proc where placeholders r added  im sending the banner for a particular email template which is i_email_cd

   io_email_replace_vals(179).fieldname := '|V_BANNER|';

 this one i had replaced in the values part

  IF i_email_cd = 'APPROVAL_COMPLETE_BOM_2T_FULFILMENT' THEN
     
      IF v_db_name<>'DMPROD'
      THEN
      io_email_replace_vals (179).fieldvalue :=
      '============= THE FOLLOWING SECTION WILL NOT APPEAR ON PRODUCTION ============= ' || CHR(10) ||
      'DB = ' ||v_db_name  || CHR(10) ||
      'TO = sthota@cisco.com'  || CHR(10) ||
      'CC = kuchoudh@cisco.com'  || CHR(10) ||
      'BCC= <bcc>' ;
     
      ELSE
      io_email_replace_vals (179).fieldvalue := '';
     
      END IF;
       END IF;

finally in the proc where the mail is generated i have to attach this text where the data is getting inserted in a table
So for tht i added this
  IF i_email_cd = 'APPROVAL_COMPLETE_BOM_2T_FULFILMENT' THEN
     
             IF v_db_name<>'DMPROD' THEN
             
           
             o_email_text := io_email_replace_vals(179).fieldname||o_email_text ;
           
             o_email_to := 'sthota@cisco.com';
             v_message_to:=o_email_to;
             v_message_cc:= o_email_to;
  insert into table {
................
                            }
so the problem is i have to add that placeholder containing |v_banner| as a global variable or global constant
is the above given code correct and if i have to define a global variable for the placeholder how do u define it and where