Germany

the only case I can think of for multiple service types
on one invoice might be a service job in another EU
country with the supply of spare parts needed for
the repair of whatever item.
tried to get something useful by adding a Line Custom Field
as a column and using L and S for the according Types.
Could not find a Line Custom Field for a Custom Report setup.

The only useful workaround I found so far is what I showed
already above

Did additional research, but all help I found, explained
how to create an invoice for goods supply and how to create
invoices for other services, but no combination of both.

to have it the simple way, I would suggest to create two
separate invoices, one for Goods Supply and one for other
services with all additional required information to be
shown and printed on documents.

having these two custom fields ( VAT-Id and Type of Service )
will also help with the creation of account forms for income
accounts which are not availabe when creating invoices for
inventory sales. Inventory sales will automatically be posted
to the standard income sales account.

Custom Report for Account Form:

Account Form:

AccountForm

for example, EU and Third Country Goods supply use other
accounts than domestic sales.

the currently offered German Localisation does not claim to
be complete, but offers a basic setup to start.
More Accounts, tax codes, report categories, report transformations
required for other types of businesses can be added by users