Most m-Fin reports render PDF in landscape orientation. A few do not, however, such as m-Fin OUTSTANDING ENCUMBRANCES. You can override this.

Rather than clicking on the report name itself, use its Run with options button.

Ignore everything here and proceed directly into the advanced options.

Change format to PDF, and orientation to Landscape.

Ignore the other distractions on this page and simply click the Run button.

The report prompts as usual. Then when you click the Finish button it will render in landscape PDF.