Follow the below tax to use Tax manager :-
● Default Tax management is possible to add by following Admin-> Catalog-> Category Tax
Management as mentioned in the screenshot taken for category, state, county and city tax
values for any Products.

● System Configuration

You can create a new state from Admin > Sales > Local Tax manager > States Manager

● You can create new counties and assign them to states from Admin > Sales > Local Tax manager
> Counties Menu

● To assign a State Tax go to Admin > Sales > Local Tax manager > States Tax Select a category
from left side to which you want to assign a tax. You can assign County and City taxes similarly
from the County and State Menu respectively]

●Tax manager will add a new customer registration address field county. This field will display all the
created counties of the state in a drop down box. Now, the Front-end of the “Tax Manager” calculates
Tax value on each product/category in the cart based on the State, County, City entered in shipping
address by a customer. Kindly refer screenshot for the same.