https://support.atlassian.com/confluence-cloud/docs/add-formatting-to-your-page/
Layouts
The layout of your pages can have a big influence on how they're read, and what visual impact your content has. Narrower columns, for example, optimize for readability, with around 50-75 characters per line, but wider page widths work better for displaying tabular data.
You can create different layouts in Confluence after inserting a default layout using the Layouts tool, giving different parts of your page a different column configuration.
There are several column layouts available. After inserting a layout, you can easily switch between the options. Content doesn't get lost when you change the column layout; additional columns are added to the right, and when you change to a layout with fewer columns, the content moves to the left. This replaces the add, remove, and move section functionality of the legacy editor.
Layouts can be moved from the page by selecting the trash can icon in the floating toolbar.