This feature is available in Identity Server. Therefore you can install the identity-mgt feature to API Manager and configure it. Follow given steps to install the feature.
1. Log in to API manager management console and go to configure -> feature -> feature management.
2. Add repository http://dist.wso2.org/p2/carbon/releases/turing/ and click on 'Find Features'.
3.Once features are listed you can select Identity Management feature and install it.
4. Go to <APIM_HOME>/repository/conf/security/identity-mgt.properties and add below configuration.
5. Restart server.