The Custom menu widget allows you to display pages, categories, and custom links with a single widget.
To use you first need to set up your custom menu in Appearance > Menu.
Here’s what it looks like when it’s added to a sidebar:

Settings
Once you add the widget to your sidebar in Appearance > Widgets, you’ll see the widget settings look like this:

Title: Allows you to add your own custom title. For example, Class Information.
Select Menu: Use this to select which of the custom menus you want to display.
Remember you first need to set up your custom menu in Appearance > Menu.