The internal control system of small and medium-sized enterprises should start from supply, production and sales. Simply put, it is to grasp the following three key areas: supply, production and sales. The control of these three key points and key areas is mainly carried out through financial control. That is to say, it is necessary to establish a financial management system for supply (mainly the selection of product suppliers and the management of accounts payable) and production (mainly the control of product production costs, including the control of water and electricity costs and the control of raw and auxiliary materials input, etc.). ) and sales (mainly the management of accounts receivable recovery, the management of sales expenses payment and the management of salesman's commission), and strictly implement it (with the system, implementation is the key). I hope I can help you.