Question: In Identity Server features I see "Multi-factor authentication" but I don't see how to configure it in the product ! All I see is configuring a local authentication with either login/password or IWA...

Answer: 
WSO2IS does not support for multi-factor authentication by default. It has capabilities to support it. Because you can implement and plug custom authenticators for WSO2IS. However there is no any multi-factor authenticator which is shipped with it. But there is some plan to ship a `FIDO` authenticator with WSO2IS next release. Git from [here](https://github.com/wso2/carbon-identity/tree/master/components/application-authenticators/org.wso2.carbon.identity.application.authenticator.fido). However, WSO2IS can easily support multi-step authentication. It means that you can configure to authenticate the user from multiple IDPs as multiple steps.(Authenticate with FB and Google both)
To have multi-factor authentication, add multiple identity providers to a single service provider. An example of this is detailed [here](http://xacmlinfo.org/2015/09/01/configure-multiple-federated-identity-providers-with-wso2-identity-server-wso2is/). In that example, Asela shows how to set multiple federated providers as a choice, but they can be employed sequentially by adding additional 'authentication steps'.