For your Shop page, Navigate to Pages > Shop > Edit > Scroll down until you see the following:
And select the format with no sidebar (or any format you’d like)
For your Shop Categories, repeat the process.
Navigate to Products > Categories and edit the category you’d like to change. Look for the area just like the screenshot above and select the format with no sidebar.
You can edit the layout on an individual product bases as well by repeating the process on the product page.