OTRS is described as 'Leading cloud-based help desk and process automation solution. It is used by service teams to improve customer relationships, reduce costs, improve communication and streamline workflows' and is a Help Desk platform in the business & commerce category. There are more than 50 alternatives to OTRS for a variety of platforms, including Web-based, SaaS, Windows, Android and Self-Hosted apps. The best OTRS alternative is Spiceworks, which is free. Other great apps like OTRS are Zendesk, GLPI, monday service and Jira Service Management.
I used in my company. Very good.