There are several ways to obtain the details of a wireless network in a Windows system. You can always open settings in the Windows Control Panel but the method for finding the wireless settings is somewhat different in different versions of Windows and can involve a number of steps. There are two other approaches that apply to Windows 7 through 10 that I find easier, especially in Windows 8.1 and 10. In general, you will need administrative privileges to find a password.
Use the free utility WirelessKeyView
One of the many free utilities from Nirsoft is WirelessKeyView, currently in version 1.71. It will reveal your password with just a click. An example of the interface is shown in the graphic below. Administrative privileges are required. It is a portable program, requiring no installation. There are both 32- and 64-bit versions and here is the download link. The download is a zipped file of only 80 KB. It is said to work in Windows XP on up.
A useful feature of the program is that it provides for the export and import of a password by means of a text file. This makes setting up a new connection for a Windows device very easy. Because it reveals a password, some anti-malware programs may flag WirelessKeyView. There was one flag out of 55 scans by VirusTotal. However, Nirsoft is a proven source of useful and safe utilities.
Use the Command Line
Users of the command line have a quick method available. Open a command prompt with administrative rights and enter: netsh wlan show profile name="ConnectionName" key=clear
In the command, you will have to replace ConnectionName with the actual name of your particular wireless connection. Retain the quote marks. A variety of information about your connection will be shown. Your password will be displayed in a section called Security settings next to an entry Key content.
If you have forgotten the name of your connection, you can find it by first running the following command: netsh wlan show profiles
The command line also provides a quick way to save the password to a file for future reference. Run the command: netsh wlan show profile name="ConnectionName" key=clear C:\wireless-data.txt
The file path and name C:\wireless-data.txt used above is just an example. The name and location of the file can be anything you like.