Select a resolution from the drop down list. To do this, navigate to Display → Change resolution. One of the ways to change the monitor's display resolution at is to edit it via the Control Panel. If you are using a multimonitor setup with iGPU rendering, you may need to disconnect and/or disable the secondary monitor(s) to change the scaling settings, and reconnect after applying, otherwise the configuration will always reset to default. No scaling: This option will not scale your desktop at all, instead centering it at the middle of the display.If your desktop aspect ratio differs from that of your display, your desktop will appear stretched disproportionately. Full-screen: This option will stretch the desktop to fit the display, regardless of the desktop aspect ratio.Thus, if you have previously changed your desktop aspect ratio and it differs from that of your monitor display, black bars will appear at the left/right or top/bottom of the display. Aspect ratio: This option will scale up the desktop to fit the monitor whilst maintaining the desktops aspect ratio.
The 'Scaling' tab allows to adjust the former, with several options available: