SHassan 1) if i've a department with 3 agents and help topic routed to these dep. would osticket assign tickets equally on the 3 agents ?
It would put the tickets in the Department (container) it would not assign a ticket to a group of individuals (Agents). You could have it assign the ticket a single agent, but it would not be a round robin style as it will always be that one person.
There are a couple older mods that might point you in the right direction but they are really old:
v1.9.x - https://github.com/monkiki/osTicket-Addons
not sure what version - https://github.com/berezuev/osticket-spreader
There are also some conversations here on the forums.
The first one I found was: https://forum.osticket.com/d/76849-round-robin-feature
There might be more options here:
https://tmib.net/resources-for-osticket/
SHassan 2) if a help topic assigned to department why i can't see it in the "Assigned to" column as it's always blank ? only when assigned to team it shows the team name .
Because a ticket being in a Department is not an assignation. Tickets are Assigned to Agents or Teams.
SHassan 3) if ticket is assigned to an agent how to deny other agents in same team to claim/transfer/edit/reply on this ticket ?
On a specific ticket you cannot. On the agent level you can edit their Role to not be able to Assign, Edit, Transfer.