Also in the purchasing information I have cost of sale
You're on the right track, Fran.
When purchasing an item from your QuickBooks Online (QBO) account, it'll use the default stock asset account.
On the other hand, you have the option to change the account in tracking your product/service item. For more insights about this, you can always check this article: Add product and service items to QuickBooks Online.
In case you want to change the account of your item, I recommend working with your accountant in choosing the right one. This way, we can guarantee the accuracy of your book after making these changes. If you don't have one, you can visit our ProAdvisor page and look for one from there.
I'm also adding this link for reference in case you need to change your product and service item types. This resource can walk you through the process seamlessly.
Tag me in your reply if you have other follow-up questions managing your product/service item. I'll be more than happy to help you. Have a good one!