I am working on Azure Service Fabric Reliable Actor implementation. Any idea/link on where can I store the Configuration value (e.g. DB connection string) and how to access that in code.
A Service Fabric application consists of the code package, a config package, and the data (https://azure.microsoft.com/en-gb/documentation/articles/service-fabric-application-model/).
You can use the config package to store and retrieve any kind of key-value pairs you need e.g. a connection string. Have a look at this article https://azure.microsoft.com/en-us/documentation/articles/service-fabric-manage-multiple-environment-app-configuration/ for more information.