To do this, open Elementor's admin area, and click on the “Widgets” tab. PRO TIP: Adding widgets to Elementor can be done by going to the Widgets tab and clicking on the Add Widget button.
How do I add widgets to Hello Elementor theme?
Once you have the Widgets menu available to you, you can assign Widgets to the Sidebar as usual in Appearance > Widgets. You can then use this Sidebar anywhere on your Elementor page. Simply add a column in a section and drag the Sidebar widget into the column.