Maker/Checker is a control system within corporate internet banking: the Maker initiates the transfer or order, and the Checker reviews and approves it before execution.
The benefit is that no single person can initiate and process transactions alone, which reduces errors and internal fraud.
If the company's payment volume is significant, ask the bank to activate multiple access levels and appropriate authorization limits.
The figures, fees and limits in this answer vary by bank and change over time — confirm them with your bank or the official source before acting.