As an architect, part of my job, lies in design, communication and documentation. Documents, (UML)diagrams and white board pictures(my favorite !) are necessary parts of defining and describing a system & application architecture.
Last week I heard a podcast where they were talking about arc42, a template for documenting of software architectures:
Here is a sample of documentation created with it: https://rawgit.com/aim42/htmlSanityCheck/master/build/html5/hsc_arc42.html