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 (Product_ID VARCHAR)

### Question ###
What is the product ID of the most frequently ordered item on invoices?

### Accurate SQL ###

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