There are two ways to add content to your page under the Column Content. The 2 ways are the Visual tab & Text tab
The Visual editor allows you too easily change text styles, add numbered & bullet lists, and other features to help create pages quick & efficiently.
Learn more: https://make.wordpress.org/support/user-manual/editors/visual-editor/
Another way to add content is to use the Text editor:
Note: The text editor uses HTML. Learn more about using HTML: https://www.w3schools.com/html/