Magento 2 customize default customer module

Question

I am new into Magento. I want to add a profile image upload functionality for the customer. All the tutorials i am getting explains new module creation. I want the change in existing module as told. Please advice .

Answer 1

You should not change a core module's code because it will break upgrading (or will be broken by the upgrading).
Anyway, you should create a new module for it.
I recommend to use plugins in your module to modify a core module's behaviour.
http://devdocs.magento.com/guides/v2.0/extension-dev-guide/plugins.html