I think the word, write-up, refers to anything you write. I am going to make up two examples with it.
(1a) Thank you for your birthday. I really enjoyed reading your write-up in it.
(2a) We had a great trip to the USA. After that, we had reflections on our experience there. When I read my friends' write-ups about their experience, I found out that we had very different opinions about the trip.
Am I using the word correctly? Thank you very much for your valuable time and help.