Is there a place to put notes on customer such as when you last contacted them, etc.

Yes, there is, Steve.

You'll want to open your customer profile and enter the details of your last encounter with them. I'd be glad to guide you how.

1. Go to the Sales menu in your QuickBooks Online (QBO) account.
2. Select the Customers tab.
3. Locate and select your preferred customer.
4. Click Edit.
5. Go to the Notes tab from the Customer information window. 
6. Enter the details and click Save.

Furthermore, I've got you this article that can guide you in billing your customer for the service or product they bought from you: Create invoices in QuickBooks Online.

You can always count on me if you have any other concerns or questions about managing your customers and invoices. It's always my pleasure to help you anytime. Keep safe and more power to your business!