changes to cad file

I need minor adjustments made to a CAD file for manufacturing purposes. The ideal candidate should have experience with CAD software and be able to make precise adjustments to the file. There is no preferred software, but proficiency in AutoCAD, SolidWorks or Fusion360 is preferred. The modifications required are not significant and should be able to be completed efficiently.

We basicaly want to add a hole to a step file and turn the opening that is star shaped to a square shape opening