1. Navigate to Catalog on the left sidebar.
2. Open Products and choose the store where you want to add tax on.
There are 2 ways to apply a tax on a specific product:
3. Go to the product you want to add the tax on and choose the Tax type that you've created earlier.
Let's go on with the 2nd way:
4. Click the product name.
5. Scroll down to Price, open Tax dropdown, and choose the tax type that you've created earlier.
6. Don't forget to Save the Product.
That's it. Learn more about how to apply taxes by bulk.