Oracle 21c

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ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS';
CREATE TABLE MyTable (docid, caseid, status) AS
SELECT '1', '123', 'X' FROM DUAL UNION ALL
SELECT '2', '456', 'X' FROM DUAL UNION ALL
SELECT '3', '123', 'X' FROM DUAL;
3 rows affected

DECLARE
  TYPE docid_list IS TABLE OF MyTable.DocID%TYPE;
  v_UpdatedDocId docid_list;
BEGIN
  UPDATE MyTable
  SET    Status='A'
  WHERE  CaseId='123'
  RETURNING DocId BULK COLLECT INTO v_UpdatedDocId;

  FOR i IN 1 .. v_UpdatedDocId.COUNT LOOP
    DBMS_OUTPUT.PUT_LINE(v_UpdatedDocId(i));
  END LOOP;
END;
/
1 rows affected

dbms_output:
1
3

CREATE PACKAGE package_name AS
  TYPE STRING_MAP IS TABLE OF VARCHAR2(20) INDEX BY BINARY_INTEGER;
END;
/
DECLARE
  v_array package_name.string_map;
BEGIN
  UPDATE MyTable
  SET    Status='A'
  WHERE  CaseId='123'
  RETURNING DocId BULK COLLECT INTO v_array;

  FOR i IN 1 .. v_array.COUNT LOOP
    DBMS_OUTPUT.PUT_LINE(v_array(i));
  END LOOP;

  -- :UpdatedDocId := v_array;
END;
/
1 rows affected

dbms_output:
1
3