Add the sample code below to your child theme's functions.php file or in a site specific plugin.

```
<?php
//* Do NOT include the opening php tag

//* Add CSS to hide All Registrations CSV Report for non-admins
add_action('admin_head', 'ee_hide_all_registrations_csv_report_non_admins');

function ee_hide_all_registrations_csv_report_non_admins() {
global $user_level;
    if ($user_level != '10' ) {
  echo '<style>a#all-registrations-csv-report.button-primary { display:none; }</style>';
}}
```