You need two products: to work with .odt (Open Document format) and to work with pdf.
For Open Document, you can use Independentsoft ODF .NET:
http://www.independentsoft.de/odf/[
^]. Unfortunately, this is proprietary product. You can try to find something else.
For pdf, you can use an Open Source .NET port of Open Source iText called iTextSharp, see:
http://en.wikipedia.org/wiki/IText[
^],
http://itextpdf.com/[
^],
http://sourceforge.net/projects/itextsharp/[
^].
Another pdf product is Open Source PDFSharp,
http://pdfsharp.com/PDFsharp/[
^].
—SA