It depends on the scope of the work and where you live. Swapping a window into the same opening is treated differently from changing the size of an opening, adding a window, or altering structural framing. We confirm the rules for your address and pull any permits needed as part of your project.

Inside Indianapolis
Building permits within the city are handled by the Department of Business and Neighborhood Services (DBNS). Changes to opening sizes, structural headers, or bedroom egress windows are the most likely to require a permit.
Historic districts
Homes in a locally designated historic district, such as Irvington, may need a Certificate of Appropriateness from the Indianapolis Historic Preservation Commission before exterior changes. Check this before you order windows.
Suburbs
Carmel, Fishers, Noblesville, Westfield, Greenwood, and other surrounding cities and towns each have their own building departments and rules.
HOAs
Many neighborhoods require HOA approval for window color or style changes. We provide specs and color samples for your application.
Rules change, so we verify requirements for every job rather than relying on a general answer.