Google Connect (register + login) for PrestaShop is an addon that allows to create buttons to log in with google plus account.
Customers with one mouse click can create account in your shop and log in to your store. It is worth to use this kind of social login addon to build useful website with better customer experience
more informations about google login module you can find on official module page here:
You can find there only valuable solutions for your e-commerce shop based on PrestaShop engine. Search the best plugin for your store that will meet your requirements and just use it.