Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE INVOICES (payment_method_code VARCHAR)

### Question ###
What is the payment method code used by the most orders?

### Accurate SQL ###

SELECT payment_method_code FROM INVOICES GROUP BY payment_method_code ORDER BY COUNT(*) DESC LIMIT 1