Sometimes, organizations will want the Quick Launch menu displayed on most of their pages but not all of them. In this situation, it's effective to use the master page to handle the preferred scenario and use page layouts
to handle the exceptions.
However, to use the page layout option, you need to know how to create a custom page layout, create a new CSS file, and reference the CSS file in the page layout. You also need to keep in mind that only publishing sites utilize page layouts.
If you're using a publishing site template that displays the Quick Launch menu, you can hide that menu on a specific page by using a page layout to override the Quick Launch menu control in the master page.
This is a popular option when an organization doesn't want the Quick Launch menu to appear on its home publishing page but wants the menu to appear on all other pages.
This scenario is so common that SharePoint provides an out-of-the-box page layout—WelcomeSplash.aspx—that overrides the master page and removes the Quick Launch menu. For every page that this page layout is applied to, the Quick Launch menu is hidden.
Although WelcomeSplash.aspx is convenient, many people find that it doesn’t fit their needs because it isn’t tailored to their content. So, here's how to hide the Quick Launch menu from a particular page using a custom page layout: