Can not find the functions.php file.

Hi,
I have two question as below.
1, I would remove or hide “add to cart” button at shop page and category page.
I install Woocommerce Catalog Visibility plug and install it, http://docs.woothemes.com/document/catalog-visibility-options/
Now, the single product no be displaied price and “add to cart”, but it still be displaied at shop page and category page.
I serach your Topic below, but I can’t find the functions.php file at Appearance > Editor.
https://hb-themes.com/forum/all/topic/remove-add-to-cart-button/

2, How to change “shop” to “stone” at http://www.westoneslate.com/stone-products/

Kindest regards,
Wang Cheng