Does we have required base or Essentials license for using Device administrator?
is this from the device side? or ISE side? device-side essential is good enough for device admin (that is the base License for Cisco at 9300 switches)
other switch models' bases should be good.
ISE - If you looking only at device administration, base License is good enough
How many license we have required for Using Device administrator?
Depending on size of devices you have you can buy packs as per the below numbers :
Cisco ISE Licensing