David Jenkins was my PhD supervisor and he taught me how to write for a PhD, using the formal style expected in academia. He did this through discussion and by closely editing my draft documents. Those documents were printed (it was before Microsoft Word) and handed back to me, almost obliterated with red pen. The mistakes I continue to make are all my own!
It was an era when professors had more time available to spend with their PhD researchers, but even so, what he did for me was extraordinarily generous. By doing this, he ‘paid it forward’ and I do the same, most of the time, with the PhD researchers that I supervise, and the junior faculty that I mentor. But I use Word and other online tools for marking up documents.