Design Professionals and Permit Applications.

When, and why, do I need an Architect - or an Engineer?

Most residential alterations, additions or repairs will require a Building Permit. The process and requirements vary by municipality but the following is generally true:

Permits are issued by the Authority Having Jurisdiction as defined in the State Building Codes

The Authority Having Jurisdiction is the Building Department of your local municipality.

This might be the city, town or village in which you live, and may or may not match your zip code.
 
The person designated as the Building Official - again, as defined by the State Code - may be known as the Building Inspector, Chief Building Inspector, Building Commissioner etc.

Depending on the degree of complexity of the project, drawings will likely need to be submitted as part of the application, and those drawings will need to be stamped, or sealed, and signed, by the Design Professional.

The Design Professional may be a Registered Architect (RA) or a Professional Engineer (PE). 
Larger and more involved projects may require both an Architect and an Engineer.