How to download the source package for a software inside repository?

[Dedeco Balaco]

Hello. Using synaptic, how to download the source package for a software downloaded from a repository used by synaptic?

I searched all the packages with the name of an open source project, and no package contain its source code. As an example, i tried to find claws-mail program source code inside the Debian repository where i downloaded and installed it using synaptic. Is it possible? How?

I want to avoid using the command line, if possible, and i believe it probably is.

Thank you