Answering that will make useful answers much easier for us to give... (^_^)
Good luck and have a good day.
If you are using Windows computer, you could follow the steps below.
1. Open a new Control Panel window. In the Control Panel you should see at the top of the window and to the right a blue link that says "Wi-Fi" and the name of your router. Click that blue link.
2. This will open the Wi-Fi Status window. Now click the Wireless Properties button.
3. This opens yet another window with two tabs. Click on the one called Security. Then click the Show characters check box to reveal your password in the "Network security key" text entry box. Copy down your password and you're done.
If you want to view the Wi-Fi password saved in iPhone, you can get help with the details in this article: How to View Saved Wi-Fi Passwords on My iPhone