Honzuki no Botsuraku Reijou, Shousetsuka wo Otetsudai Suru.
The protagonist, Emma, has no family and is left in the care of terrible relatives. One day, she gets a job at a novelist's mansion. She was told not to enter the workroom, but she accidentally reads the original manuscript and ends up pointing out a hole in the work. A spacious bathroom, a fluffy bed, and unlimited access to books! A relaxed life as a live-in maid in a big mansion!
(Source: Comic Days, translated)