Hi,
Ok, let's start with the basics.
I am using:
- Jira Cloud.
- 2 new custom fields:
- Text Field (multi-line) (Service Version in attached pic)
- Select List (single choice) (Dev Service in attached pic)
I have:
- Assigned them correctly to my issue type.
- Can see both fields on my issues.
Questions:

From the attached screenshot you can see Service Version is in the Description Area and Dev Service is in the Primary Fields section.
- How do you define which of the areas (Description Area, Primary Fields, Secondary Fields) a custom field will be displayed?
- How can you change where custom fields are displayed?
Thanks in advance for any help.
Paul