This post function creates a new issue with the specified parameters.
...
The project of the new issue can be the same as the project of the issue transitioned. It can also be set to be another project. If you have some other requirement where the project changes based on some data of the issue, you can use “Calculated” option. This option will require you to provide a Jira Expression that returns a project. The result of the Jira Expression will be used as the project of the new issue.
...
Similar to the Project, Issue Type can be also calculated. In this case, you need to provide a Jira Expression that returns an issue type as result.
If you select an Issue Link Type, the newly created issue will be linked to the issue transitioned with the selected issue link type.
...
You can copy all the applicable fields from the issue transitioned to the newly created issue, or you can prefer to copy only some set of them. If you copy only some set of them, you need to provide Jira Expressions for each field you would like to copy, which will give the value of the field for the new issue.
...