A good 'Service Writer' (the term you use for this job) isn't cheap and typically aren't outsourced. Usually because your (local) competition is going to be using them too. And also because customers aren't going to trust a person that is writing service for multiple shops.

That said, a good service writer is worth their weight in gold. Also, they are typically going to be the person you end up selling the business to when you retire. Most mechanics aren't good enough at the business side of things to actually buy, but service writers are.