Kishitan wa Jouheki no Naka ni Hanahiraku

Taking arms and protecting the people, Knights. And the apprenticeship period to obtain that title…… The job of a knight apprentice is not to practice with the sword nor ride horses, but anywhere from taking care of horses to laundry; all sorts of odd jobs. At the Padlock Castle, Claustra, the story of the knight apprentice Rosa begins!

source https://readmanga.re/manga/kishitan-wa-jouheki-no-naka-ni-hanahiraku/