Hi
How can I import STL file into hyperwork desktop (to use hypermesh function)? I am using HyperWorks 2020 student edition. And in the Import Solver Deck only have a few option (OptiStruct, Radioss, H3D and FEKO).
And how can I convert tri-mesh STL file into hex-mesh using Hypermesh?
Thank you.

If you can not found STL in the list, it means that you can not import this format.
About creating hex mesh from STL, it depends to the geometry presented by STL. If the geometry is simple, it's possible.