There are various issue tracking tools that have been available for many years on the market. There are tools such as Bugzilla used primarily for bug tracking. There is another popular tool called Mantis that provides a good set of features, which again is used for bug tracking. Companies who are already using some of these tools and now want to move to JIRA can migrate their data using various importers provided by JIRA out of the box.
Follow these steps to perform the CSV import:
Navigate to JIRA Administration | System | External System Import (Under IMPORT & EXPORT).
You will get the list of various importers as shown in the following screenshot: