Two sets of plans and/or a scope or work are required for plan review.  Plans generally require a drawing which includes the existing structure, proposed changes, measurements, etc.  Although they do not always need to be drawn to scale, they do need to have the measurements marked, and they should include materials used and how those materials will be installed.  The more detail, the better.  Basically, the plans should be drawn in such a way that someone else could use them to build exactly what the plans were intended to build.
A scope of work can sometimes be submitted for smaller projects such as commercial reroofs, resides, windows and doors.  Again, see our handouts for more information, and for Scope of Work forms related to particular project types.