Godot needs to call rcedit to change the exported project icon and metadata (such as the “Company” field displayed when hovering the executable in Windows Explorer). This program is not distributed with Godot, but can be downloaded from this page (choose rcedit-x64.exe on a 64-bit machine).
Once you have downloaded the rcedit executable, place it somewhere, open the Editor Settings, go to the Export → Windows section then specify the path to the rcedit executable in the Rcedit property.
Note: If you are exporting from Linux or macOS, you will need to install WINE to be able to run rcedit.
i downloaded it and put it in rcedit but the icon is still the default icon