If you cannot drag and drop, this is generally due to the use of Internet Explorer or older versions of Microsoft Edge to edit with Elementor.
It is not possible to edit with older versions of Microsoft browsers. Please edit Elementor pages with Safari, Chrome, Firefox, or Microsoft Edge, version 79 or greater. Microsoft’s newest version of Edge, which was first released in January of 2020 is now based on Chromium (which Google Chrome is also based on), and therefore it is now compatible with editing with Elementor.
Of course, pages built with Elementor do show up in the browsers of Microsoft on the front end.