There is the option to hide the fields and buttons you do not want visible in the invoice application. The settings are made in the administration tool under the menu option System configuration - GUI settings and made per instance.

The list contains 7 main options:

Invoice header

This form applies to the fields at the top of the invoice window

Invoice info

This form applies to the fields on the Invoice info tab

Other

This form applies to the fields on the Other tab

Black menu bar in the invoice window

This form applies to the buttons that show / hide the different sections with invoice information in the invoice window.

Black menu bar in the queue window

This form applies to the buttons that show / hide the different sections with invoice information in the queue window.

Black menu bar global

This form applies to the buttons which is always on the black menu bar.

Buttons and fields in the invoice window

This form applies to the buttons found in the invoice window.

Parts of the sub form All sub forms are structured in the same way but the forms that only contain button settings do not have the fields for determining the width
Size At the top of the form you can specify the width of the fields. The fact that there is both the largest and the smallest width is because the fields adapt to the size of the screen. It is also possible to determine how many columns the fields should be divided into.
Item Here you decide in which order buttons and fields should be displayed. Change the numbers in the Position field to get the order you want. Check/uncheck the Visible check box to decide if the button/field should be displayed in the work queue/invoice window.
Groups The Invoice head section is divided into two groups, which means that the fields in Group 2 will always be to the right of the fields in Group 1.The other parts have only one group