If you need to see how many active users you have in  Dynamics 365 / 365  - this KB article will walk you through the steps. 

Steps to Find active users

  • Click on the Advanced Find in the top right corner
  • Under Look For , choose Users
  • Set the Status  Attribute Equals Enabled.
  • Set the next condition to Access Mode
  • Set this equal to Read-write and Write
  • Click the Results button
  • The number of active users is displayed in the bottom left hand corner.