With Deep Clone (Cloud Only) it is possible to clone an issue with all of the forms attached to it. This can also be automated using a Deep Clone’s post function on a transition.
Make sure to select the Clone issue properties when cloning an issue.
Note that currently, Deep Clone can only be used to clone within the same instance. You cannot clone issues across instances.
Cloning issues & forms between projects
Cloning an issue to another project, which does not have have the same custom fields as the source projects will often break the link between form fields and the Jira custom field.
Recommendation: If you plan on cloning an issue between projects, only link form fields to standard Jira field, or ensure that the same custom fields are available in both projects.