Converting a PDF to a (TI-Nspire Document) file is typically done to view text, images, or data on a Texas Instruments TI-Nspire graphing calculator. While "TNS" can also refer to Oracle configuration files, in the context of file conversion, it almost always refers to these calculator documents. Top Online PDF to TNS Converters
A specialized tool often used for more advanced conversions (often requires technical knowledge of the Lua scripting standard). GitHub/Sathariels TNSConverter: