I want to take a backup. The online help says this is an option under Settings. However, this is not true. The option does not appear under Settings. Any suggestions?

You should consider to convert your data to QB Desktop and use the trial version to access your historical data for good.

Thank you for taking the time to post your concern here in the Community, declan-monaghan. Allow me to elaborate and clarify things for you so you can get back to working order.

The backup and restore feature is exclusively available in QuickBooks Online (QBO) Advanced. If you're using a different QBO Subscription, you can run reports in QBO and export them in Excel format for backup by following these steps:

1. Go to Settings, then Export data.
2. On the Reports or List tab, set the date range.
3. Add or remove items from the Reports and Lists tabs by turning the switch on or off.
4. Select Export to Excel.

For more information, you can check the link: Export reports, lists, and other data from QuickBooks Online

Alternatively, you can visit the Intuit App Center to view supported apps that can help you backup the QuickBooks Online data.

Furthermore, here are some things to be aware of regarding the lifespan of your QuickBooks Online data after cancellation and reactivate your account in the event that you'd like to subscribe again in the future. We would be delighted to have you back!

If you have more questions about backing up your files, you can always go back to this thread. I'll be around to help.