HotDocs created the .hpd file extension; many people in the legal profession use it to transfer documents. It is a variation on the .PDF file but is viewed using the HotDocs Player. The .hpd file can be opened by the HotDocs Player you simply click open, and then select your file, it will then be displayed in the viewer. Much in the same way that Adobe displays .PDF documents. The file is mainly used by legal firms to transfer documents, and contains a simple document, for example, scanned images.