You can use the Geospatial Data Abstraction Library (GDAL). It has gdal_translate for HDF to geoTIFF. The same feature is in QGIS and GRASS and runs on multiple platforms.
The best way to convert from HDF to TIFF would be to use a library like GDAL (https://gdal.org/). Here is a sample code using GDAL to convert from HDF to TIFF: