Hi @Sal Singapore,

Thank you for posting here in the Community. I can provide some clarification about the authenticator app.

You can use any email address to set up a Google Authenticator with your QuickBooks account. First, you'll need to generate a new QR code which you can use in the app.

For the option to be visible, please make sure to disable the Two-step verification. The Turn on Authenticator app option should show after turning off the previous security verification.

In case you need the steps, here's how:

1. Go to: accounts.intuit.com.
2. Sign in using your Intuit credentials. When prompted to use a code from Authenticator app, select I don't have a code. You'll be guided to request a code via text message.
3. Select Sign in & security, then Two-step verification.
4. In the Two-step verification section, select Turn Off. You will then be asked to enter your password to proceed.
5. Select Turn on Authenticator app to turn it back on.
6. Follow the next steps to receive a new QR code.
7. Enter the code to link to your new device, then select Verify and save.

If the option is still unavailable, I recommend you proceed with contacting our QuickBooks Support Team. They'll be able to assist you further with this feature.

Our Customer Support Team is available from 6 AM - 6 PM PT (Monday - Friday) and 6 AM - 3 PM PT (Saturday). You can reach them through these steps:

1. Click the Help menu at the upper right. 
2. Go to the Search tab.
3. Choose Contact Us. 
4. Enter your specific concern in the What can we help you with? box. 
5. Click Let's talk. 
6. Select Get a callback or Start a chat. 
7. Enter your contact information. 
8. Choose Confirm my call or Send message.

For additional reference, I've attached a link you can use to learn about the QuickBooks multi-factor authentication: Verify your account with multi-factor authentication.

Drop me a comment below if you have any other questions regarding your account. I'll be happy to help you some more.