A built-in tool that allows users to perform calculations and add "calculator tapes" as PDF annotations.

Unofficial modifications to the software's core code frequently lead to crashes, data loss, or incompatibility with newer operating systems. Official Features of Foxit Reader & Editor 12.0

The 12.0 series of Foxit software introduced several legitimate enhancements designed for productivity:

Improved tools for importing and exporting comments in various formats like FDF and XFDF. Legitimate Ways to Use Foxit

If you have purchased a license, you can activate it directly within the app via the Help menu's Activate button.