Adding Non-Inventory Items to Sales Invoices

I am trying to get to grips with Manager and have some queries.

We charge our customers labour, travel etc and need these on the sales invoices, however, obviously they are not going to be inventory items.

Can anyone please advise me how non-inventory items can be added in to sales invoices?
I have created non-inventory items but can’t find them in the create sales invoice window or anywhere else except in settings.

Many thanks for any help you can give me.

They show in the same Item drop down list as inventory items. Make sure they are defined as able to be sold.

Many thanks I should have seen that, but unfortunately a bit long in the tooth!