A QML component provides a way of defining a new type that you can re-use in other QML files. A component is like a black box; it interacts with the outside world through properties, signals, and slots, and is generally defined in its own QML file. You can import components to screens and applications.
You can use the following QML elements to create components:
Border Image uses an image as a border or background.
Image adds a bitmap to the scene. You can stretch and tile images.
Item is the most basic of all visual items in QML. Even though it has no visual appearance, it defines all the properties that are common across visual items, such as the x and y position, width and height, anchoring, and key handling.
Rectangle adds a rectangle that is painted with a solid fill color and an optional border. You can also use the radius property to create rounded rectangles.