Hello there, @pamvanart.

I got your point on how important to set a default period in the Sales graph. However, the period that we can select is limited, and we're unable to customize a specific time on this page.

Still, you'll see your sales data from this graph by choosing the corresponding time. The closest time that you can select is the This year by quarter and Last year by quarter option. Take note that you can still select other options.

In case you want to run a detailed sales report, you can generate the Sales by Customer Detail report and customize it. Here's how:

1. On the left panel, click Reports.

2. Type Sales by Customer Detail in the search box.

3. Choose the Report period, and click the Customize button.

4. Click Filter to expand, and choose the customer you want to view from the Customer drop-down list.

5. Select Run Report.

You can also check this article for additional tips and information: Customize reports in QuickBooks Online.

Please know that you're always welcome to post if you have any other concerns. Wishing you and your business continued success.