By default, the WooCommerce Shop Page only outputs an “Add to Cart” button for simple products. It will output a “Select Options” button for variable products. This is probably very useful for most use-cases.
On the other hand, perhaps you would like to give your customers the option to select product variations directly from the Shop page rather than forcing them to click through to the single product page. This can be done with a simple PHP snippet. The following snippet will also add a quantity input for simple products (as well as variable products)
Which will result in a similar output on the front end:
You will probably need some custom CSS to help the layout along just a little bit. This may or may not work with your theme, but should serve as an example:
Not sure what to do with code snippets? See What Do I Do With These Code Snippets?