How to copy network security key from wifi

When I was at a customer site, I connected my Windows-10 computer to a Wifi. Now, every time I go there, I don't need to enter anything anymore, I can just connect to that Wifi.

Now I have a colleague who wants to connect to that Wifi too, and I would like to pass him that key. Where is it stored on my computer?

Edit In the meantime I check the entire registry, I didn't find anything.

The Wireless network I'm talking about has been configured, but it is not the network I'm working on now. While checking the network and sharing centre, I am able to work on the current network and to setup a new one, but where do I need to go in order to obtain information from the existing ones?

Hereby a screenshot of where I currently am: I am connected to "Telenet-34919", but I would like to obtain information from another Wifi:

Thanks in advance

You can use WirelessKeyView from Nirsoft to list all the WiFi access points you've connected to and their associated saved password. You don't need to install anything, just run the provided executable.

It's worth noting that both Windows Defender and Microsoft SmartScreen will flag the application as potentially malicious - this is because you can use the tool to extract a WiFi password that you wouldn't normally have had easy access to.

There is no key to pass - only the password is required.

To display the password for an SSID, run the Command Prompt (CMD) and enter the following command:

netsh wlan show profile "SSID" key=clear | findstr "Key Content"

To show the names of all your stored credentials:

netsh wlan show profile