Product (services) to quotes?

Please tell us about the module products ( services). When selecting in the offer or in another module (invoice, contract). services cannot be selected from the list, they are not. How to make a choice?
Thank!

Services are created on the fly on a Quote/Invoice/Contract.

They are not products and do not reside in a module but are simply entered into the aos_products_quotes table when added as line items.

Thanks,

Will.