I would like to get elevation from a satellite image. I would be needing resolution less than or equal to 5 m. Is this possible? If yes, how can I procure these images and where?
Generally speaking, if you have a Single Image (Single or Multi Band), you cannot get Elevation information from it directly.
If you have a Stereo Image Pair, you might be able to get some Elevation values from it, but even those are not accurate without a rough base DEM, or Benchmark.
You also get satellite data, which consists exclusively of a DEM. For example the ASTER DEM, which gives you elevation values of a region.
I am aware of some commercial providers who supply a satellite derived DEM 10m, but I am not aware of any that supply Satellite DEM with a resolution of 5 m or lower (I'm not sure if that is even possible).
Good experience with NextMap DSMs, https://store.intermap.com/MapShop.aspx?GeoLocation=World .
They're aquired by airborne SAR, but only available for europe and the US.