A creation form defines the dialog that your team will see when defining incidents.
You can completely customize the content and order of the fields in the creation form. Custom fields can be included and default fields can be deleted, as shown below.
When creating your incident type's creation form, click an item on the left to customize or delete it on the right. Also, note the purple circle icon below the fields, when you click it you can add any additional field types of your choice.
Click Update creation form to confirm the changes you've made to the creation form.