Organizations need to exchange information simple and efficient, with costs as low as possible. Such information is ussually presented as documents with pre-defined content. These documents may be equivalent or almost equivalent but quite distinct in different organizations. The same document can be different depending on the historical context. Also, organizations do not always use the same technology to generate your documents. The purpose of this work is to enable interoperability of documents and achieve portability of digital documents through the reuse of content and format in different plausible combinations. We propose the characterization of digital documents using ontologies as a solution to the problem of lack of interoperability in the implementations of document formats. As proof of concept we consider the portability between OOXML and ODF document formats.