The names of fields on the order header screen can be changed or removed.

To see this you will need to select the Menu option: Setup > Field headings > All fields (Global) or Setup > Field Headings > All Fields (Area: XXX)

Click the drop down for 'Order header details' and it will show the fields -

You can change the name by entering the required text against each field under the Replacement Name heading.

You can use control values as required also, for example:

*nv = Field Not Visible

*ro = Field Read Only

*me = Field Mandatory