Functional Requirements are MUST-TO-HAVE (without these requirement the system or part of the system will not function)

Non-Functional Requirement are NICE-TO-HAVE (without these requirement the system will work, however it will help to enhance the usability and performance of the system. ex. when you have entering product code in cashier system you can do it by manual entering the product code by keyboard or use the scanner to read the code. the scanner is enhancing your usability of the system)