How to hide the sidebar from your pages or posts.
This is especially useful if you’re creating a landing page.
While creating a new page, simply scroll down to Page Attributes and choose the “full width template” from the drop down as shown below.
Depending on which theme you’re using, you will also have additional options like the “blank landing page” or “full width template plain” which hides even the menus and footers.
If you’d like to hide the sidebar from all of your posts, then navigate to Dashboard > Appearance > Widgets, delete all the widgets under the sidebar area, and put an empty text widget in place.