SCOTT@xe>create or replace package faq
  2  as
  3    procedure test1
  4    ( p_param1 in varchar2 := 'NOTHING'
  5    );
  6  end faq;
  7  /

Package created.

SCOTT@xe>create or replace package body faq
  2  as
  3    procedure test1
  4    ( p_param1 in varchar2
  5    ) is
  6    begin
  7      dbms_output.put_line('p_param1 is '||p_param1);
  8    end test1;
  9  end faq;
 10  /

Package body created.

SCOTT@xe>exec faq.test1;
p_param1 is NOTHING

PL/SQL procedure successfully completed.