Hi there lakle1 and welcome to our community
By "platform", do you mean to ask about PC, Mac, LINUX/UNIX?
Or are you instead asking about the Output? (.CHM vs
WebHelp/FlashHelp)?
RoboHelp only runs in Windows. As for the output, you would
typically want a .CHM if you want the user to access the help off
the local C drive. Or WebHelp/FlashHelp if you plan to deploy via a
company intranet or off the internet.
Hopefully this helps some... Rick