Wireframing is the next step after prototyping. Once a design has been created and tested, it is important to communicate the design such that everyone can see how it should function.
Wireframes include notes on content, functionality, behaviour and supported controls. This is particularly important for responsive interfaces and designs supported across multiple platforms.
We can create wireframes in a number of styles, from simple images with callouts to full specifications of behaviour. The depth we document to really depends on your need.