Place the book in the Ghost Room or high-activity areas. If the ghost roams away from the book during its interaction window (every 45–90 seconds), it won't write.
To get the ghost to "write-up" its evidence, you must follow specific placement and interaction rules: Fazmofobi
If you witness a ghost event, try placing the book directly at the ghost's feet; they are highly likely to interact with nearby items immediately after an event. Place the book in the Ghost Room or high-activity areas