Saijakushoku no Shokyuu Majutsushi: Shokyuu Mahou wo Kiwametara Itsunomanika "Sen no Majutsushi" to Yobaretei Mashita.

Kirisaki Runo was caught up in the Heroes summoning and came to another world. As he was not the hero, he did not receive any special abilities. The only magic he could use was elementary magic which could at most create a light gust or ignite a small fire. He had received the world’s weakest job, elementary magician. Branded as useless by the inhabitants of the other world, Runo was not put down due to his optimistic character and had fun polishing his magic. Eventually, he discovered the secret nature of elementary magic—the freedom to create spells as one wished, and made up his mind to live through the other world with his ability! Source: AlphaPolis