I want to create social login in magento2.I want to add google and facebook as social login.Could anyone explain me how to add this functionality in magent2 without using any extension. I dont want to use any extension.
First of all there are few free extensions for social login you my check. However if you don't want to use existing module than definitely you have to create your own module for social login.
For hints you may check existing modules currently exist in magento marketplace analyze theme and than you may build your own.