I May Be a Guild Receptionist, but I'll Solo Any Boss to Clock Out on Time, Vol. 1 (manga) by Mato Kousaka

Alina Clover thought being a receptionist for the Adventurers Guild would be her ticket to the good life...but her dream gig turns into an overtime nightmare whenever adventurers get stuck clearing a dungeon. To save herself from paperwork, Alina turns to the simplest solution at hand?_"beating down the monsters herself!
Binding: Paperback / softback