Seijo Wa Tokku Ni Shoukansareteiru. Nihon Ni. summary:

She was supposed to have been summoned as a saintess, but instead got thrown into a country called Japan. Alexandra Ollier, a.k.a. "Rei Natsukawa", hides her magical powers and works as an office worker for a small company in modern Japan. "As long as I can live peacefully and uneventfully, this is fine." says Rei, who faces many small troubles standing in the way of her lifestyle.Follow Rei Natsukawa, a mage possessing high level magical powers, and her seemingly ordinary yet not-so-ordinary story..(Source: Young Champion)