.indd is a proprietary format from Adobe. It is the default file extension for projects created with Adobe InDesign.

This program is used to create books, magazines or other layouts for works which get published. It can be opened with programs from Adobe (InDesign, InCopy) or QuarkXpress (with ID2Q Plug-in).

In InDesign it is also possible to save the project as a PDF. It can then no longer be changed, but is better suited for archiving.

Advantages:

- Various layout options

Disadvantages:

- proprietary