Autodesk PowerMill offers various post processors for different CNC machines and controllers. You can find a list of available post processors in the PowerMill documentation or on the Autodesk website.
You're looking for a PowerMill 4-axis post processor download. Here's some informative content to help you: powermill 4 axis post processor download
In PowerMill, a post processor is a software component that converts the toolpath data generated by the software into a format that can be understood by a specific CNC machine. The post processor is responsible for translating the toolpath data into G-code, which is the standard language used by CNC machines. powermill 4 axis post processor download