From the Home screen, navigate: Settings icon(located in the lower-left) > Network & Internet. If the Windows Settings options are not visible, tap or click the Settings Home icon (located in the upper-left) to go to the Settings home page.
Tap or click Wi-Fi, then tap or click Manage known networks. If not available, refer to Microsoft's Manage wireless network profiles article and follow the instructions for "Show all wireless profiles on the PC" and "Delete a profile".