Typically, functional requirements will specify a behaviour or function, for example: “Display the name, total size, available space and format of a flash drive connected to the USB port.” Other examples are “add customer” and “print invoice”.
Yes. A successful software development project relies on the development team being able to meet all of the functional requirements while also meeting the non-functional requirements. This is important because it helps ensure that the software is ready for use, that is, is working, and that it is necessary for the project.