How to edit existing page

Or:

1. Go to Dashboard → Pages → All Pages. 
2. Choose the Page from the list and click on the button Edit with Elementor. 
3. Then find the section/element you want to edit. 
4. Customize chosen shortcode using the settings panel from the left and save the changes.

Detailed information on how to create or edit pages using Elementor you can read in this Documentation

Elementor uses three main block areas: Sections, Columns, and Widgets.

Sections are the largest building blocks, and inside them are groups of Columns.   Columns sit inside of Sections and are used to house the Widgets. Widgets are placed inside of Columns.
You control the   Section, Column, and Widgets with their handle.

To edit the Section, Column, or Widget, Right Click their handle. 

Section

1. Click the   icon to create a Section
2. Set your Column structure 
3. Right-click to Edit, Duplicate, Copy, Delete, etc.

Note: Learn more about Sections here

Column

1. Set the Columns Width. You can do it under Layout, or drag the dashed line between the Columns.
2. To add more Columns Right Click > Add New Column
3. Insert Widgets to your Columns

Note: Learn more about Columns here

Widget

1. Insert Widgets inside your Columns
2. A Widget width is set by the Column width