If you are synchronizing with either of the accounting integrations then you will initially set-up your taxes within those accounting applications and synchronize taxes into Kickserv. The tax rates must originate from your accounting application to successfully sync back and forth within invoices.
Once you have your sales tax(es) set-up in your accounting software they will sync over to Kickserv on the initial sync. You can add new tax rates and sync them to Kickserv later as an option too.
Once your initial sync has successfully completed you can then create Kickserv customer records and add the appropriate tax rate for them.
Pro Tip: Ensure that your customer record has a chosen tax rate prior to creating the first opportunity or job.
Extra! Extra! - Taxes in the U.S. are associated with your customer record. The customer receives the tax rate, but the charge items are simply marked taxable or not taxable.