Which system to choose for tickets?

Question

Helpdesk

Small IT outsourcing.
I am looking for something that allows you to keep an up-to-date list of applications and receive feedback on them from employees.
Let's say clients tell me about a problem, I create a ticket on the phone (I really want to have an application for android) and attach it to Ivan, an employee. He immediately gives a warning on his phone, preferably such that without confirming the receipt of the application, he could not close the window.
Or if clients call Ivan directly (there is such a thing, we will get rid of it) - then he could make an application himself and, for example, then unsubscribe about the progress of solving the problem. But what could not be removed, only added.
I've looked at a lot of questions and just got more confused.

Answer 1

Any tracker has to be cut for yourself. There are not so many support trackers - ManageEngine, RequestTracker, OTRS... But they all involve communication exclusively by mail, no one has developed a tracker specifically for outsourcing. There are development trackers - bugzilla, redmine, TRAC, but again they are all designed to work by mail.