How can you see disk quota details?

The real answer is:
repquota -a because if you put only repquota in the command line is going to tell you
Bad number of arguments. Then show you differents Options…

repquota: Utility for reporting quotas.
Usage:
repquota [-vugsi] [-c|C] [-t|n] [-F quotaformat] (-a | mntpoint)

-v, –verbose display also users/groups without any usage
-u, –user display information about users
-g, –group display information about groups
-s, –human-readable show numbers in human friendly units (MB, GB, …)
-t, –truncate-names truncate names to 9 characters
-p, –raw-grace print grace time in seconds since epoch
-n, –no-names do not translate uid/gid to name
-i, –no-autofs avoid autofs mountpoints
-c, –batch-translation translate big number of ids at once
-C, –no-batch-translation translate ids one by one
-F, –format=formatname report information for specific format
-h, –help display this help message and exit
-V, –version display version information and exit

The repquota -a show you this for example>
*** Report for user quotas on device /dev/mapper/Vhome-Lhome
Block grace time: 7days; Inode grace time: 7days
Block limits File limits
User used soft hard grace used soft hard grace
———————————————————————-
root — 36 0 0 8 0 0
www-data — 636 0 0 24 0 0
yourusers — 23284 102400 122880 1563 0 0