By default, a limited number of icons and application shortcuts are placed on the desktop screen. But you can increase the grid of icons by reducing their size. You can set the size of the desktop and the position of the icons in the Phone Settings.
Open Settings – Desktop – Desktop Grid. Or use the settings search (search bar at the top of the screen).
Different values are available depending on your device. On Xiaomi 4 × 5, 5 × 5 grid is available. Here, in the settings, you can activate the automatic filling of cells of free space on the desktop.
After all the settings, go to your desktop to see the result.