Hi,
Sorry you're not seeing this option. It looks like that's the text in our Help Center article, and it's a little out of date (and I'll make sure we update it to match the current wording!).
To turn on ecommerce for a profile, sign in to your account and go to the Admin page (where you see the columns for Account, Property, and View). Select the View you want from the drop down. Click "View Settings". On this page (it should say "Reporting View Settings" at the top of the page) scroll down until you see a section called "Ecommerce Settings". There should be a toggle right underneath that title. Click it to turn it off/on, then click "save" at the very bottom of the page.
Hope this helps you find it! Don't forget, too, that after this setting is turned on in your account, you also have to change your tracking code to get ecommerce data in your account.
Best,
Analytics Academy Staff