While creating sub-tasks, it is not possible to select a type of subtask.
I went in the configuration board to create a new type of subtask but I can only create a new type of task.
Thank you for your help.
Welcome to Atlassian Community!
At this moment, Sub-tasks are not implemented in JIRA Next-gen projects, although it's currently added in the "Coming Soon" section of our Public Roadmap:
For more details about the steps of our developers on its implementation, feel free to watch the suggestion below to receive notifications about any updates:
Let me know if you still have any questions.