I have PRISM data which is in the following format.
Are there any ways (software and methods) to extract the DEM or elevation information from these data files?
Yes. I worked with JAXA data and I could easily import it in QGIS. Did you try importing IMG-ALPSMN234433460-01B2G_UN? If I am not mistaken it is a raster, and creating a DEM is very straightforward in QGIS. Could you provide us with the info of the summary.txt?