Download Mi Flash tool from above download links first. Open the folder where you have placed or downloaded this tool. Now, Extract the Downloaded zip file in your Windows PC.Make sure that you have uninstalled any Previous version of Mi Flash Tool.

Download https://sourceforge.net/projects/microsindo/files/Xiaomi%20Tools/

Bootloader unlocker utility to unlock the Android bootloader of all Xiaomi devices running any version of MIUI/HyperOs. All Mi unlock tools version added download section