How can I custom the display order in customer portal?

[Administrator]

I want to modify the order of the displayed fields in the customer portal, and additional I need to custom the field "Select a system" with a custom list.

Where can I change these configurations?

[Walter Buggenhout]

If you just want to change the fields' order on the screen, go to your Service Desk project (Resiflex) and then go to Project Settings (on the bottom left of your screen, possibly represented by a cog icon).

Then select Request types and locate the "Report a system problem" request type. Over there, click "Edit fields". Using simple drag and drop, you can reorder the fields as you like.

Regarding the systems list, there are 2 possibilities. I am guessing that they are Components. If so, this page explains how you can manage those. If they are not, they are managed through a custom field. Custom fields are managed in the Administration section of JIRA and managing them requires a bit more background. If needed, have a look at this documentation page.