I appreciate you for posting your concern here today, @Leslie123123.

Currently, you won't be able to switch to the new experience once you're back on the old one. Rest assured that this capability will be available in the future.

Moreover, you can submit a feature request to our Product Developers if you want the new experience to opt back permanently.

On top of that, visit this article to learn more about how you can personalize and add specific info to your invoice and other form styles in QBO: Customize invoices, estimates, and sales receipts in QuickBooks Online.

Please know that you're always welcome to post a reply in this thread if you have any other questions about your QBO account. I'll be here ready to assist you. Have a great day ahead!