I've created a content type with a product reference field, but when I create a content with the reference to the product, it shows add to cart form with only add to cart button. I wanted to display Price, quantity, and product attributes on the add to cart form. I've searched a lot to find out any configuration for this, but no luck. Can anyone please help me regarding this?. It works fine in Drupal 7, but in Drupal 8 there is no way I can set up the form.
First be aware that Commerce is still in Alpha, so behavior might change between versions!
I suppose you are looking for something like this from the Drupal Commerce Blog.
I have no idea how to get there as I am awaiting a more stable version of Drupal Commerce, but I suppose the breadcrumb in the image should give you some directions on where to find these settings.
I wanted to address your question Sky Buzz, regarding exposing the 'quantity' field and an 'editable price field' with the 'add to cart form' on product pages.
I posted the below here: https://www.drupal.org/node/2702989#comment-12134795
For posterity, I wanted to post the solution I found here, as I ran in to similar symptoms with Commerce 2.x with D8, only to learn I wasn't looking the right places.
Regarding exposing the quantity field, that is done at Commerce > Configuration > Order Item Types > Default > Manage Form Display > the Add to Cart display.
There you can move the quantity field out of the "disabled section"
or here on my site: /admin/commerce/config/order-item-types/default/edit/form-display/add_to_cart
as mentioned here: https://drupalcommerce.org/blog/44226/commerce-20-alpha3-released
Regarding price showing up as an editable field, this happens if you move the "Unit Price" field up out of the "disabled" section" on the SAME PAGE mentioned above. So i recommend NOT doing that (not sure in what context that'd be used for, but it's a gotcha for some).
The price output happens on the Product Variation Type manage display or here on my site: /admin/commerce/config/product-variation-types/default/edit/display
There, you can move the Price out of the "disabled section" as it should be by default (or SKU, etc).