Since Tails 5.8 (December 2022), your data corresponding to each feature of the Persistent Storage is stored to the USB stick immediately. You don't have to restart Tails anymore after enabling a new feature.
For example, when you enable the Tor Browser Bookmarks feature of the Persistent Storage, your current bookmarks are saved in the Persistent Storage immediately.
To open the <span class="filename">Persistent</span> folder, choose <span class="menuchoice"> <span class="guimenu">Places</span> ▸ <span class="guimenuitem">Persistent</span></span>.
When the Printers feature is turned on, the [[configuration of the printers|doc/sensitive_documents/printing_and_scanning]] is saved in the Persistent Storage.