The second and third level menu items can have a widget area assigned. Please follow the guide below.

Step 1  Navigate to Dashboard >> Appearance >> Widget >> Widgets in Menu

Step 2  Drag and drop suitable widgets on the left side to the Widgets in Menu. Give the new widget a name and save it.

Add widgets to the menu
Add widgets to the menu

Step 3  Go to Appearance >> Menu, look at the left-hand side, find the box titled widgets, select the widgets you would like to add the menu.

Add Widgets to the Menu
Add Widgets to the Menu

IMPORTANT NOTE: If your can not find the box titled Widgets on the left-hand side, please expand the Screen Options, check the Widgets as shown below:

expand screen options
Expand Screen Options