How to Hide Menu from Specific Page in WordPress

To hide main menu or certain blocks upon a unique page or post access, simply follow these steps:

1. Open the page edit page from administrator view
2. Add a new ‘Custom HTML’ block
3. Add CSS style using these following codes below, and then save the page/post edit.

<style>
             body.page-id-xxx header#top, body.page-id-xxx div#header-space, body.page-id-xxx footer{
                    display: none !important;
             }
</style>

To check on the page or post ID, just look it up from the HTML generated from web browser’s Inspect feature.