Most photoediting software will show the EXIF metadata
But you can also get specific apps for it (like EXIF Viewer for iOS)
There is also the possibility to use free websites for reading such info (at the price of individually uploading the pictures - and with various success or limitations), f.i.
www.metadata2go.com
exifdata.com
exif-viewer.com
etc.
In the past the iPhoto app on iOS also supported viewing the EXIF data, something that is missing with Photos
Edit - adding
On OSX open a photo with the PREVIEW, then from the menu use Tools > Show Inspector > (i) > EXIF / IPTC