What is a project file? How can you produce one for your project?

What is a project file? How can you produce one for your project? Qt interview Question
· Projects are described by the contents of project (.pro) files. The information within these is used by qmake to generate a Makefile containing all the commands that are needed to build each project.
· you only need to run qmake [ a project-oriented system for managing the build process for applications, libraries, and other components] on this project file.
· By default, qmake generates a Makefile that you use to build the project, and you can run your platform's make tool to build the project.