What are the import and export formats available?

Import: RSDOC, ECAD files (IDF, IDB, EMN), OBJ, SKP, STEP (read only), STL, TXT, JPG, BMP, PNG
Export: RSDOC, AMF, DXF, OBJ, 3D PDF (facets only), SKP, STL, XAML, JPG, PNG

Full STEP and IGES format support is available with the DSM Exchange and Bundle optional add-on modules: https://designspark.zendesk.com/hc/en-us/articles/211867685