How to check if the PC is running in HDR mode?

To perform a basic check, please open the Display settings page. Look for an option called Play HDR games and APPs and ensure it is enabled. Scroll down to the bottom of the page and enter the Windows HD Color settings submenu to inspect visible differences between SDR and HDR video images.
The detailed confirmation is as follows:
1. Verify whether you are running the appropriate version of Windows. For external monitors (displays and TVs), you need version 1803 or higher. For integrated panels on laptops or all-in-one PCs, you need version 1903 or higher. Check your Windows version by typing winver in the Start button search or command window. If using an older version of Windows 10, update through the Check for updates process accessed via the start or command window, following update instructions;
2. Confirm whether your GPU has the latest video drivers from Intel, NVIDIA, or AMD;
3. Verify whether Windows has enabled HDR mode on the appropriate display. Right-click on a blank area of the desktop, select Display settings from the popup window. If multiple displays are connected, choose the HDR-capable display. Under the Windows HD Color section, below Display capabilities, select Play HDR games and APPs to enable HDR mode. Check the monitor's on-screen menu to confirm HDR mode is enabled. After adjusting the monitor's on-screen menu, you will need to reset the display or restart the PC.
Note:
If the Play HDR games and APPs button is absent, your PC's GPU can not support HDR, or your PC can not recognize the display as HDR-capable.