I use JIRA at work for reporting bugs. I haven't used Stash, but according to Atlassian (the maker of JIRA): "Atlassian Stash is the Git repository management solution for enterprise teams." From: https://confluence.atlassian.com/display/STASH025/Getting+started+with+Git+and+Stash
@anvai9 Not sure how much you've worked with Git, you may already know this, Git and Github aren't the same thing. Github is a site where you can store your code and other assets in repositories by using Git. There are other sites that also allow you to do this, like Gitlab. And apparently Stash, which is made by Atlassian, who also makes JIRA.
You can see a tutorial on that site linked above. I couldn't see on that page whether you have to pay for Stash, but I'm guessing you do, since it's made for businesses to use, apparently, like JIRA.
Also, my company uses JIRA for tracking bugs and tasks, but we use Bitbucket for version control. Not sure what the advantage of Stash would be.
Thank you for your explanation @jonwilson! I hope this helps @anvai9. As you said later, I've heard about people using JIRA to manage tasks and bugs/issues.