According to the JIRA Core 7.1.x release notes: https://confluence.atlassian.com/jiracore/jira-core-7-1-x-release-notes-802161668.html#JIRACore7.1.xreleasenotes-createlinkedissue
This "Create new linked issue" feature was added to JIRA core beginning with the release of JIRA 7.1.0. However the problem seems to be that this feature is only available from within Business specific projects. When viewing issues within a JIRA Software project, there is no option to create new linked issue here.
- Create a new JIRA Software project and create at least 1 issue
- Open this issue and navigate to the MORE menu
Expected to see an option to "Create new linked issue" from this drop down menu
This option does not exist from within issues in software projects
Perhaps this is a core specific feature that JIRA Software has not yet implemented. But it seems to be that JIRA Software projects ought to be able to perform this same task.
In theory you could create the issues in a different way and then link them together, but honestly that defeats the intended purpose of this feature.