The account connection component is used so merchants can connect or disconnect their store to various accounts. For example, if merchants want to use the Facebook sales channel, they need to connect their Facebook account to their Shopify store.
Button group displays multiple related actions stacked or in a horizontal row to help with arrangement and spacing.
Buttons are used primarily for actions, such as “Add”, “Close”, “Cancel”, or “Save”. Plain buttons, which look similar to links, are used for less important or less commonly used actions, such as “view shipping settings”.
Page actions let merchants take key actions at the bottom of specific pages in the interface. This is important because sometimes the primary call to action is hard to access when merchants are at the bottom of a page.