We did something similar and used workflow via SharePoint Designer to copy the ID field into a field called "Issue Number". The workflow gets triggered automatically on Create / Edit (we included edit because the field can be modified by the user on the edit form and if that happens we want the number refreshed with the actual ID).
Before you create the workflow in SharePoint Designer, you need to add a column called "Issue Number" to the list you want to tweak.
- List item
- Open Sharepoint Designer
- List item
- Click File New -> Workflow
- Give a name for the workflow
a. select the list from the dropdown
b. Uncheck Allow this workflow to be manually started and check automatically start on new and change then press Next
- Give the step a name like "Assign Issue Number"
- Create a Condition
If Compare a field -> If Issue Number not equals Current_Item:ID
- Create an Action
Update List Item -> Set Issue Number to Current_Item:ID
- Press Finished and test out by creating a new issue.
*The Issue Number will appear on the form and if you have emails setup to notify on assignment it will appear in the reassigned template.
*It will not appear in the created email confirmation because the workflow gets triggered after that email was executed.