Go to Admin -> Setup Receivables -> Sales Taxes.

Click the "General Sales Tax Info" icon.

Indicate up to 3 taxes for your "Sales Tax District For Walkins" in the Sales Tax 1, Sales tax 2, and Sales Tax 3 boxes by using the drop down menu.

This tax will now appear when creating a POS order.

You can also create a tax group by clicking "Additional POS Tax Groups - Click to Add or Update"

***POS orders use the Walk-In tax rate because the nature of POS says the sale is happening in your business. So if you tax using the Order By Address POS will use the taxes listed in the Sales Tax District for WalkIns instead of those listed specifically for that customer.

If you make a Fulfillment Order instead it will use the customer's tax rate.