Charlotte's Letter(2019)

Charlotte, a bookworm who dreams of becoming a writer, starts her new job as a maid for Lord Matthew and his sister Lady Anna, the last remaining members of the Parvens family. Her ability to write catches the attention of them both. Now, for Matthew, she is tasked to write letters pretending to be him, while for Anna, she must secretly report on Matthew's day-to-day affairs. Putting pen to paper has never been so difficult! What will become of Charlotte when the Parvens family's twisted deceptions come to light?

(Source: Tappytoon)