I'm here to ensure you'll be able to create a journal entry in your QuickBooks Online (QBO).
Aren't you able to find the Plus (+) icon at the top right corner of your QBO? If yes, try to check the + New button at the top left corner. If you happen to locate the "+ New" icon from there, it means that your QuickBooks is already updated. The latest update of QuickBooks includes the interface of the page.
However, if you can't still see the Plus(+) icon from there, let's try logging into your QBO account using a private browser. There are times that the browser is full of frequently-accessed page resources, thus causing websites, like QBO, to act weirdly.