Where can i find this One page checkout extension?

[Adam_Robinson]

Hi @san , 

You can consider this One Step Checkout Extension from Landofcoder. This one has the most beautiful & functional checkout interface that I have found and it may meet your requirements.

And if you want to seek for a tool to have you log in to social networking site, you can use Magento 2 Social Login also. It can provide you more other social channels you can use for your site!

Hope this assist you !

Have  a nice day !

[Swissuplabscom]

If this is the layout you're looking for: 

Please, check the FireCheckout module.