The following snippet lets you remove specific meta boxes from the main Dashboard page in WordPress. These are the default meta boxes shown on the main admin screen.
To remove or change which boxes are displayed, add this snippet to your theme’s functions.php file and choose which boxes to remove:
function my_custom_dashboard_widgets()
{
global $wp_meta_boxes;
// Main column (left):
// Browser Update Required
unset($wp_meta_boxes['dashboard']['normal']['high']['dashboard_browser_nag']);
// PHP Update Required
unset($wp_meta_boxes['dashboard']['normal']['high']['dashboard_php_nag']);
// Right Now - Comments, Posts, Pages at a glance
unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_right_now']);
// Right Now
unset($wp_meta_boxes['dashboard']['normal']['core']['network_dashboard_right_now']);
// Activity
unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_activity']);
// Site Health Status
unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_site_health']);
// Side Column (right):
// WordPress Events and News
unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_primary']);
// Quick Draft, Your Recent Drafts
unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_quick_press']);
// Recent Comments
unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_recent_comments']);
// Incoming Links
unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_incoming_links']);
// Plugins - Popular, New and Recently updated WordPress Plugins
unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_plugins']);
// Other WordPress News Feed
unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_secondary']);
// Recent Drafts List
unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_recent_drafts']);
}
add_action('wp_dashboard_setup', 'my_custom_dashboard_widgets');This is the page we are talking about:

For safe admin customizations, see What Are Child Themes and How to Use Them.