After registering a brand new account in TimeCamp and going to Invoices panel system will notify you that you haven’t defined any taxes. You’ll be able to quickly create new ones at that point by clicking on the link:
You can access these setting also by going to Settings-> add-ons -> invoices.
To create a tax structure simply fill up the form and click on the green + button. You can manage your taxes by adding the new ones, and deleting any if you decide so. You can additionally hit the “favorite” icon to make a certain tax default.