Hi Giulia
There is some information on how to do this in the file config.exeample.php . Edit the config..php file as below
// Configure the default quick access menu
// The quick access menu in Totara allows administrators to quickly access important links. They can customise their
// menu by adding and removing the items there.
// The following setting overrides the default menu that administrators will see before they begin customising it.
// Item keys are required and can currently only be found by inspecting the menu items in the browser.
// Group can be one of: platform, learn, engage, perform, configuration.
// $CFG->defaultquickaccessmenu = [
// [
// 'key' => 'item_key_1',
// 'group' => 'platform', // Optional, defaults to 'learn'
// 'label' => 'sometext', // Optional
// 'weight' => 1000 // Optional
// ],
// ['key' => 'item_key_2', 'group' => 'platform', 'label' => 'sometext', 'weight' => 2000],
// ['key' => 'item_key_3', 'group' => 'learn', 'label' => 'sometext', 'weight' => 3000],
// ];
To find out the key values open the quick access menu administration as an admin "/user/quickaccessmenu.php" and inspect individual menu entries using the browser console (usually right click on the row of the item and inspect). Look for the elements containing the "data-quickaccesssettings-item-key" property. This is the value for the key.
Regards