Hello,I want a report which contains "Estimates by product/service"

Hello, @pandegsa.

You can use the Sales by Product/Service Detail report and filter it to non-posting to view the estimates. Let me guide you how.

1. Go to Reports.
2. Enter Sales by Product/Service Detail in the search field.
3. Select Customize, and then tap Filter.
4. Mark the box next to Transaction Type, and then choose Non-Posting.
5. Click Run report. See the image below.

Learn more about customising report in this article: Customise reports in QuickBooks Online.

In case you need help with other reports-related tasks, browse this link to go to page. It has our general reports topics and some videos. Just pick a title that'll fit your concern: Reports.

Please let me know if you have other questions or concerns about estimates or with reports. I'll be around for you. Take care and have a good one.