In Elementary POS office (https://app.elementarypos.com) select menu->Sales.
Press "Show filters" and select tax. You will see the total for the selected period.
All possible sales information can be found in the sales report in Excel. There are several workbooks, one of which contains detailed information about sales tax.
The report can be obtained in the Elementary POS office, select menu->Export sales.
If you don't have Excel, the report can be opened in Libre Office (free app).
