I would like a report where I can see monthly sales report which has also cost price column, I would like to export and do some more calculations on the file. Any help?

I'll walk you through how to get your monthly sales report, urooj.

Let's use the Sales by Products & Service Detail report to filter the information you'd like to see. Then, we can export it to Excel so you'll be able to do some calculations.

Here's how: 

1. Go to the Reports menu.
2. Enter Sales by Products & Service Detail, then click to open.
3. In the Report Period drop-down menu, choose the correct date.
4. On the Rows/Columns, click Change columns, then place a checkmark beside Sales Price.
5. On the Filter section, you can select the details you'd like to see.
6. Click Run report.

Once done, click on the Export icon, then select Export to Excel.

For your visual reference, I've attached a screenshot below.

For more information about personalising your reports, I suggest checking this article: Customise Reports in QuickBooks Online.

Aside from exporting, you can also memorise your reports in QuickBooks. This helps you save the current customised settings for future use.

I encourage sharing your concerns or questions with us in case you have any. This way, we'll be able to help you out.