Click on "Settings" (1)  --> "..More" from any screen

In the list click on "Taxes" (2)

You can create as many taxes as you need
1. Enter Tax name
2. Enter Tax rate
3. Is this Tax the default one? Yes or No. Only one Tax can be the default one.
4. Hit "Add" to save the new Tax 
5. Clicking on an existing Tax will activate the edit mode