For example, when the job is shipped out of state. I've changed my sales tax rates in Preferences, but it didn't affect my clients. Our state requires us to collect sales tax on the entire invoice when the job produces a tangible product, but to collect no sales tax on concept-only jobs. All of these sales tax regulations are confusing. Then when the job is added the task settings are copied to the job ticket.
Sales tax is added to the invoice's total.
First, check to see that the sales tax rate copied over from the client's file correctly. If the rate isn't there you'll need to add the rate into the client's Billing Information as well. If the rate is there, it means when the invoice was added they did not tab through the invoice completely. The other possibility is that the tasks are not marked as taxable. Double-click on each task on the invoice to see if it is marked for sales tax and change it if necessary.