When you setup 2fa, the service provider should tell you write down some text, and that is the secret you should backup. If you didn't do that, you can also backup your secrets by following steps:
Remove passphrase if you set it in security menu. You can set it to empty to remove it.
Go to export/import, and backup the code you can see in the text area box.
Hi,
Could you please let me know, how to take backup secret of Authenticator google chrome app.
Thanks! Pavan