in my experience with woocommerce, there are two ways.

1 - Add some extra css to your current theme.

For example I want to modify the title of the product : 

I open the chrome inspector, I see that the product page has a class css for `body.single-product`.

The product container has a class css `div.product` (create by woocommerce itself `<div id = "product - <? php the_ID ();?>" <? php wc_product_class ('', $ product);? >>`).

so, I can apply my own style, (for example my theme displays the title in an `h1` tag of css class `product-title`) 

So ; i cann override by : 

    body.single.single-product div.product h1.product-title {
      color: #13345f;
      font-size: 1.5em;
      font-weight: 800;
    }

and so for the other elements in my product page.

2 - Second method, and that you create your own templates: `your-theme/woocomerce /` , and use `wc_get_template_part()`