How to create a cascade field

To create a cascade field with 3 or more levels of specification, you must have Jira Administrator permission.

In the “Issues” configuration page in Jira, in the custom field page, select Create custom field

In the Advanced tab, you should see the 3 additional custom field types our app adds to your instance.

Select the one that best suit your need, give the field a name and a description if necessary.

Later, you can add the field to a desired screen.

3+ Level Cascade Fields Documentation