Hello there, @lynda Boualili. Thanks for reaching out, and welcome to the thread.

You can switch back anytime for the new invoice layout in QuickBooks Online if you prefer to use it over the old one. In your case, you may have encountered a problem with your browser caused by too much cache being saved on your browser and creating unusual system behaviour. To resolve the issue, I recommend opening your account in a private (incognito) window. 

Here are the keyboard shortcuts to open a private browser:

• Google Chrome: press Ctrl + Shift + N
• Mozilla Firefox: press Ctrl + Shift + P
• Microsoft Edge: press Ctrl + Shift + P
• Safari: press Command + Shift +N

Once you've login via a private window, try to switch back the invoice layout. If it looks good, go back to your regular browser and clear its cache. You can also use another supported browser as an alternative.

To learn more about how the new experience can help you land jobs and get paid faster in QBO, see this article: See what’s new with estimates and invoices in QuickBooks Online.

Let me know if you have other feature concerns or questions about managing invoices in QBO. I'll gladly help. Feel free to leave a comment below. Take care!