Hi swm023,
Unfortunately, there is no screen for this table. You can however, create a screen, base it off the ActivityInvoiceType table and design a screen to create some new options. Keep in mind that the stock FieldService_AddEditWorkOrder screen uses the original values in the ActivtyInvoiceType table for some of its functions. If you are going to remove them, know where they are being called and why.
For some tips on the screen design, take a look at some of our other "Type" tables like the CRM_CaseTypeList and CRM_OpportunityTypeList screens. You could essentially copy that design for the InvoiceType screen.
Hope this helps,
- Adam