The difficulty is on-par with IELTS for essay writing but here in PTE-A we are going to type in a system than writing using a pencil. So, erasing, correcting and re-ordering of the text will be much easier. Trust me, it saves lot of time. That’s the reason we are able to write around 250+ words in PTE-A even though the given time is just 20mins. Most of the times the essays are something like give your opinion and do you agree or disagree. Try to follow Ryan (IELTS-Argumentative essays) writing videos from youtube. That will be of great help.