In this article, you’ll learn how to create a lead capture page and share page with multiple columns.
Inside the editor, click on the block which contains your elements (texts, images, etc.). Note: the block is the entire box which contains your elements. Do not click on the elements themselves as this will not open the column-changing properties on the right-hand sidebar; usually, you can do this by clicking on the outer edge just outside of your text/image/other elements which is usually transparent. Here's an example:

You'll then notice that the right side of the editor page would change and show you different column types. Simply select the number of columns you would like to have under the Property Options.
You can also select the Columns' alignment, height, change the background color or even add a background image as well.
If you're having trouble seeing the column properties on the sidebar, you might be clicking on an element (such as a text/opt-in form/image/etc. Make sure you're clicking on the box outside of the element and not the element itself as it would only open the property settings of that specific element.
(What not to click:)