SQL> ed
Wrote file afiedt.buf

  1  create or replace procedure create_user
  2     (name in varchar2,
  3     pass  in varchar2)
  4  authid current_user
  5  as
  6     str varchar2(300);
  7  begin
  8     str:='create user '||name ||' identified by '|| pass ;
  9     execute immediate str;
 10* end;
SQL> /

Procedure created.

SQL>  EXEC CREATE_USER('NEWUSER','PASSWORD');

PL/SQL procedure successfully completed.