This is one way to do it:
SQL> set serveroutput on
SQL> CREATE OR REPLACE TYPE MyType AS VARRAY(200) OF VARCHAR2(50);
2 /
Type created
SQL> CREATE OR REPLACE PROCEDURE testing (t_in MyType) IS
2 BEGIN
3 FOR i IN 1..t_in.count LOOP
4 dbms_output.put_line(t_in(i));
5 END LOOP;
6 END;
7 /
Procedure created
SQL> DECLARE
2 v_t MyType;
3 BEGIN
4 v_t := MyType();
5 v_t.EXTEND(10);
6 v_t(1) := 'this is a test';
7 v_t(2) := 'A second test line';
8 testing(v_t);
9 END;
10 /
this is a test
A second test line
To expand on my comment to @dcp's answer, here's how you could implement the solution proposed there if you wanted to use an associative array:
SQL> CREATE OR REPLACE PACKAGE p IS
2 TYPE p_type IS TABLE OF VARCHAR2(50) INDEX BY BINARY_INTEGER;
3
4 PROCEDURE pp (inp p_type);
5 END p;
6 /
Package created
SQL> CREATE OR REPLACE PACKAGE BODY p IS
2 PROCEDURE pp (inp p_type) IS
3 BEGIN
4 FOR i IN 1..inp.count LOOP
5 dbms_output.put_line(inp(i));
6 END LOOP;
7 END pp;
8 END p;
9 /
Package body created
SQL> DECLARE
2 v_t p.p_type;
3 BEGIN
4 v_t(1) := 'this is a test of p';
5 v_t(2) := 'A second test line for p';
6 p.pp(v_t);
7 END;
8 /
this is a test of p
A second test line for p
PL/SQL procedure successfully completed
SQL>
This trades creating a standalone Oracle TYPE (which cannot be an associative array) with requiring the definition of a package that can be seen by all in order that the TYPE it defines there can be used by all.