Once upon a time the dynamic range of digital images was rather limited, so HDR (using multiple exposures) was the only way to capture an image that could vaguely mimic light range of the human eye. Here is a primer
on the concept.
Various techniques were available then if you didn't want to use dedicated HDR, mainly shooting in RAW format and 'exposing to the right': slightly overexposing (but not 'burning') in order for the darker part of the image to have more data and then lower the bright parts of the image on the computer.
Now you may still want to do HDR, either to create surreal images like this one
, to really handle problematic examples like that one
However these days, you simply want to 'see more of the detail', which largely corresponds to opening up the shadows area of your photo. All modern apps will do that, starting with Apple Photos. I tend to use Lightroom but Photos will be OK on the fly. So just go in edit mode and adjust the light settings: start with exposure and then go down the list. Shadows and 'black point' will give you impressive results without the need for a separate app. This is because modern camera sensors capture files which have a lot more information these days.
One last point: said information gets 'crushed' at jpg conversion, so shooting in RAW will ALWAYS give you better results. Enjoy.
Bop 'til you drop
MB Pro 13 | i5 | 16 Gigs of shiny DDR RAM | 1TB SSD - we have arrived...
iMac 27 i5 16Gig 1TB
iPad Air 64Gig
Time Capsule 1TB | 4TB connected HD
iPhone 6: "Too big, but bloody fast..." & a bunch of ill fitting ear buds
Canon 7D proper camera with nice L glass and Lightroom 6