Backups

"It is recommended to make regular backups of your wallet even though in most cases a single backup may be sufficient. Please note that in order to recover from a backup you will also need to provide the pass phrase because backups are encrypted. Hence, if you either lose your wallet or your pass phrase you will be unable to access any of your funds again!

Backups can be obtain from the Wallet Management Console (Settings -> Wallets).
Wallet Exports

The most convenient way to create a new backup is by exporting the wallet with the provided link in the Wallet Management Console. Please store your backups safe from loss, theft, and natural catastrophes
Brainkey (advanced users ONLY)

If you never manually imported an account key into your wallet, you can alternatively backup your accounts and their funds by exporting the brainkey, a string of words from which your keys are derived deterministically.
Remark: Hierarchical Authorities (advanced uses ONLY)

If you are using hierarchical authorities (account and/or active permissions), backing up your keys alone may not be sufficient to regain access to your funds! Please revise the documentations about hierarchical authorities."