Convert PKT to PDF

Several different pkt file types exists, and none of them are formats typical for PDF exports. This means that pkt to pdf conversion is most likely not a straight file conversion, but searched by users that need to use content from .pkt files for PDF documents.

How to use Tex fonts in PDF documents

The most likely file type that is related to documents is a specific font format for TeX / Latex and these can be found  saved as .pkt files. The only way to use these fonts in your documents (that you will export to PDF format) is to install them to your system via TeX Live or MiKTeX or similar distribution.

When you create PDF document from LaTex source, you can embed any fonts to the file. Within your LaTeX document, you can specify the TeX fonts you want to use using font-related packages or commands.

Exporting Cisco Packet Tracer files

Another common .pkt file type comes from the Cisco Packet Tracer, but these files are not meant for standard PDF export. These files contain configuration and settings, so the only reason for such export is perhaps to print the settings on paper. Any text editor can probably open .pkt files and view the specific text instructions and the components of the network.

Simply put, it is impossible to convert PKT to PDF directly.
Thus, there is no so-called pkt to pdf converter or a free online .pkt to .pdf converter to be found.