I haven't used the Free Form Feature since Unigraphics had "Free Form Feature" tools under "Insert".
How could it be accessed on the last NX releases?
Where could I find them?
In the modeling application, activate the "surface" ribbon bar to find many of the free form tools. If you have a shape studio license, you may want to switch to the shape studio module to find its tools: application ribbon bar (more) or File -> applications -> all applications.