Can TAX be included in the item cost rather then added after

can TAX be included in the item cost rather then added after?

have not been able to get this to work
my items have to be added ex. tax
then the invoice will save and add tax.

can it be that the price inc. tax
and the saves and shows how much tax?

thanks

Tax positioning variables exist. So you can change pre or post positioning. Look into the code.