App Specific Passwords How to do it?

I hope to test the Postbox software and as I enter my Mac email address a message pops out asking me to create an App Specific Password using my Apple ID details.

I read as follows in the support.apple.com/en-us/HT204397.html page

Generate an app-specific password

1. Sign in to your Apple ID account page.
2. In the Security section, click Edit.
3. Click Generate Password and follow the steps on your screen.

After you generate your app-specific password, enter or paste it into the password field of the app as you would normally.

However as I enter the page following the instructions in my Security section I do not find a "Generate Password" button or something similar.

Am I doing something wrong?

Thanks