MantisBT is an open source web based bug reporting tool. You can download a standrad copy of the tool from the downloads section on the official website.
In case you don’t want to install and maintain the tool, there is an option to use the bug tool
as a service at MantisHub. MantisHub provides the tool as a service for the customers.
General workflow using Mantis is to log defects for the assigned projects. We can log defects for an assigned projects using the Report Issue button.
You can find more information about the tool at: