Hand Seals allow a person to mould chakra and then change it’s Nature to finally use a Jutsu. The first person to develop the hand seals was Indra Ōtsutsuki. However, many characters in Naruto can perform Jutsu without the use of ANY hand seals at all. I’ve made a list of all Five of them —
5. Hagoromo Ōtsutsuki
Hagoromo Ōtsutsuki was the first person born with the Rinnegan. With it’s power, he managed to learn every Jutsu the existed. Hagoromo, however, did not even require hand seals to perform a Jutsu. He could manipulate nature without forming any hand seals at all.