If you need to bill and invoice for tax only, follow these steps:
1. Add a job to the books if you want it to reference the job.
2. Go to the invoice information tab for the job.
3. Add one line item for a zero cost amount (IE: Tax Correction, 1 QTY at $0.00)
4. Click on "Taxes", then "Assign New Tax".
5. Enter in the tax item you want to charge, change it from Percentage to Dollar Amount, then enter your tax amount you want to charge. Hit "Assign" then "Apply"
6. Check the total amount for the invoice, it should be the tax amount you are looking to charge for.
NOTE: Tax WILL NOT apply if you don't have the line item.