I'm here to share details about the price rules feature in QuickBooks Online (QBO), @info1262. This way, you'll be able to determine why you're unable to turn on the said option in your account.
The price rules feature in QBO allows you to provide discounts for specific products to certain customers for a specified amount of time. Currently, the said feature is in beta testing and only available in the US version of QBO. That's why you're unable to turn it on in your international version of QuickBooks from your Account and Settings page.
In the meantime, you can manually enter the appropriate price in the Rate column when you create an invoice. Here's how:
I've attached screenshots below for your reference.
You can also manage your price rules by integrating an inventory management app in QBO that's available in your region.
Additionally, you can import your products and services from Excel to your QBO account. This way, you can easily monitor your sales and income. To learn more about this, kindly check out this article: Import products and services from Excel. It contains information for formatting tips and the things you need to consider before performing the import process.
Aside from the Sales menu, the Accounts and Settings page also has the Advanced option. It is where you can set up your accounting method, company type, and categories to name a few. You can learn more about it by checking out this article: How do I set my advanced account settings?.
Please let me know if you have other concerns. I'm just around to help. Take care always.