This is the Customization forum for Inventor where the programming interface is discussed. It's not clear what context you're talking about but I suspect you're talking about controlling the orientation of the view in the user-interface. There are a couple of things to be aware of.
The first is the view cube. You can reorient the view to any position you want and then reset what Inventor considers as front and top. Use the little drop-down by the view-cube where it has the commands to "Set Current View as" either "Top" or "Front".
The second is an application setting so you can change the default for all documents created after this. There is a "ViewCube..." button on the "Display" tab of the "Application Options" dialog. That will display a "ViewCube Options" dialog where there is a "Default ViewCube Orientation" section.
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Brian EkinsInventor and Fusion 360 API Expert
Website/Blog:
https://EkinsSolutions.com