For the key in the issue, can I manually set the key for each issue?

[hkstreetname]

For the key in each issue, currently it is a prefix + an auto increment number in JIRA work management, such as "ABCD-101". In my use case, we would like to distinguish the task hierarchy in the key and set the sequence number according the sequence of the event actual happen. 

Here is an example.

ABCD-1 Organize a meeting

ABCD-1-1 Book a room

ABCD-1-2 Send out an agenda

ABCD-1-3 Provide meeting material

ABCD-1-3-1 Prepare product factsheet

Is it possible to do it in JIRA? Any alternative?

Thanks.

[Nic Brough -Adaptavist-]

Welcome to the Atlassian Community!

No.  Jira has an issue naming scheme that you can not change, it's always <project key>-<sequence>

All you can do for your scheme is create issues and sub-tasks in the right order, so that they take on a sequence that matches your desired order.

But, relying on the issue key to sequence things is completely the wrong approach, you should be looking at useful ways to sequence your issues.

[Curt Holley]

Hi @hkstreetname 
Welcome to the Community!

It is not possible to mess with the key numbering in Jira.

But you can use a (let's say "Dependency") link type to show which task is prerequisite to another. You could add the sequence number to the beginning of the Summary to impersonate what you propose above, just not all in the key.

You can even automate all of this (if it is a repeatable sequence) See example below, Where you have the sub-tasks in order and link them via the "most recently created issue".