Windows makes this easy, as long as you're connected to the network. Open Settings > Network & Internet, then click the Change Adapter Options button (in Windows 10) or Advanced network settings > ...

hands-on You're at a place you've been before and your Windows laptop immediately remembers the SSID and password for the Wi-Fi network, logging you on automatically ...

There are multiple ways to view the Wi-Fi password, but using Settings is the easiest. The Netsh utility, accessible via Command Prompt, shows passwords for all the networks you've ever connected to.