You can edit the layout type of the pages in your store using the Storefront Builder tool. The layout type can be set separately for each specific type of pages (like the home page, category pages or product pages). The layout type determines the overall appearance of a page (namely, the number of information columns on the page and the position of the sidebar).
Here's how you can use the Storefront Builder to change the layout type of a page:
Open the Storefront Builder.
In the Storefront Builder, navigate to the page of your store for which you would like to change the layout type.
Click on the Page Layout element in the sidebar menu on the left-hand side.
This reveals a drop-down list allowing you to choose the layout type for the page.
Choose the layout type you prefer. The following layout types are supported:
One column,
Two columns with left sidebar,
Two columns with right siderbar,
Three columns.
Please note that the page layout type will be implemented for the page without further confirmation. You will see how the page looks with the new layout in the right pane of the Storefront Builder.