-- https://docs.oracle.com/en/database/oracle/oracle-database/23/lnpls/plsql-subprograms.html
DECLARE
  x INTEGER;

  FUNCTION f (n INTEGER)
  RETURN INTEGER
  IS
  BEGIN
    RETURN (n*n);
  END;

BEGIN
  DBMS_OUTPUT.PUT_LINE (
    'f returns ' || f(2) || '. Execution returns here (1).'
  );

  x := f(2);
  DBMS_OUTPUT.PUT_LINE('Execution returns here (2).');
END;
/