This action can be used, to store a tracker specific sequential/consecutive ID/Number in a custom field of the tracker item, that is subject/source of the triggering event.

For example: You have a tracker called Orders and you want each Order (item of the Orders tracker), to have a sequential/consecutive Order No.

First you define Order No as a custom Orders field with type Integer (could also be Text):

Only the submitter should have edit permission for the Order No field in the initial order status.

Then you associate a Create a new sequential id/number action with the initial state transition (Submit) of Orders:

This action has two parameters:

Field is the custom field of the tracker item, that is subject/source of the triggering event, where the number should be stored.

Prefix is an optional prefix for the sequence/number (only if the target field is a Text field).

If you specify trackerKeyName as Prefix, then the actual key name of the tracker will be used as prefix.