I'm sure you have come across those two words while you're using the system.
The deactivate button in Deskera's Sales means you suspend the users from using the system without removing them from the system. There are a few possibilities you might need to use the deactivate button is when:
a) You realized your employee is not stable to use the platform.
b) Your employee violates or misuses the system.
c) Your employee is not around for some time, etc.
Once you deactivate the user's account, their status will change to inactive.
If you choose to delete the user's account, it means you remove them from the system, and you won't be able to see their profiles again in the system.