As an example, here is a loop that performs an UPDATE statement on each row of the EMPLOYEES table (again from the Oracle test HR schema). Two local variables are set in the RETURNING clause and then used in the proceeding of the PL/SQL code:
for rec in (select * from employees)
set salary = salary * 1.05
where rec.employee_id = employee_id
returning salary, last_name into l_salary, l_name;
dbms_output.put_line(l_name || ' new salary is ' || l_salary);
More information on DML in PL/SQL in chapter 14 of Oracle PL/SQL Programming, fifth edition, by Steven Feuerstein.