QuickBooks Online automatically back up your data with same level as used by financial institutions, JP.
It's our priority to secure your data. So you don't need to worry about saving your QuickBooks file. Here's how we keep your data safe and secure.
If there are changes to your company file, your data is saved to two hard drives.
We regularly copy all data to a third-party hard drive in order to protect your data in case something happens to the first two hard drives.
Automatic backups are performed every night.
Please take note, for the reason that we update your records with every change, we can't restore your file to a previous point in time.
With regards to your second question, fixed asset management is unavailable in QuickBooks Online. But you can set up an asset account to QBO. You can refer to this article for the detailed steps: How do I set up an asset?
If there's anything else you need, you can drop a comment below. I'll be happy to help.