PDF, Word, and PowerPoint (PPTX) outputs are not HTML web pages, so meta tags are treated a bit differently. In PDF, Word, and PPTX targets, there are tabs devoted to their options. On those tabs, you will see document property fields for the PDF, Word, or PPTX file.
If your output includes meta tags, these can be found along with your other properties in the final PDF, Word, or PowerPoint document.
