The Ghost Writing Book in Phasmophobia is used to collect evidence to identify the type of ghost. Keep in mind that not all ghost types will write in the book. Having more than one book is recommended.
Placing the book with the F Key (Default Key) does seem to be less problematic than just tossing it on the ground or table. One trick that can help in placing the book is to also place a Video Camera looking at the book, so that it can be checked from the truck.
The only problem with using the Video Camera to observe the book is that the night vision light from the Video Camera can cause enough glare that it is nearly impossible to see if anything is written in the book. You can either place the book on the ground with the Video Camera looking at it from a higher vantage point or place the book against an object on its side and have the Video Camera looking straight at it. See the screenshots below for examples of using the Video Camera to keep an eye on the book.