Hide WordPress admin bar

If you want to deactivate the toolbar for your own profile, click on “Users” ” “Your Profile” in the upper right corner of the WordPress admin interface and then deactivate the item “Show toolbar for me on the website” in the middle on the right.

Hide WordPress admin bar if page preview

However, if you want to hide the toolbar when previewing a page that is being edited, this can be solved with the following code:

add_filter( 'show_admin_bar', 'show_admin_bar_if_not_preview' );
function show_admin_bar_if_not_preview($show_admin_bar) {
	return ( is_preview() ) ? false : $show_admin_bar;
}

Hide WordPress admin bar for all users

add_filter('show_admin_bar', '__return_false');