Humans are one of the most physically diverse races, in skin tone, eyes, hair, and many other attributes. They are adaptable and ambitious, perhaps owing to their relatively short lifespan compared to elves and dwarves.
You can find information on how to create human characters on D&D Beyond.
Distribution
In The Known World, it's unclear where humans originate from, and they are the most common race due to their adaptability and ingenuity.
Arauglbrok
Humans on Arauglbrok mostly come from nearby Vatan, the only other continent that shares the same side of The Great Rift, and so they share traits with these. Few humans can tolerate the heavily industrial nature of the dwarven archipelago.
Consult with your DM if you wish to play a human on this continent.
Haelspur
On Haelspur, most humanoid races are fairly uncommon. Humans from this continent mostly live in nomadic tribes, and very few have travelled here from elsewhere in the world.
Consult with your DM if you wish to play a human on this continent.
Korona Morska
Humans across the archipelago of Korona Morska are a stoic no-nonsense people, and are fairly inward-facing apart from necessary trade with nearby Tide and Rhak. Because of this, Koronans are generally less diverse than humans on other continents, mostly being of pale skin and dark hair.
It should be fine to play a human on this continent.
Rhak
Humans have adapted to many harsh environments across the large continent of Rhak. In the northern deserts, they live in ancient stone cities or live as nomadic traders on camel-back. In the southern rain and bamboo forests, humans have lived in hidden cities for thousands of years.
It should be fine to play a human on this continent.
Tabasamu La Miungu
The islands of Tabasamu La Miungu are populated by many humans, each island having a unique culture and people. Most people across the archipelago are dark skinned, though ever-increasing global trade has lead to more diversity.
It should be fine to play a human on this continent.
Tide
Humans are one of the most common races in Tide, they are diverse in appearance and geographical distribution – you can rarely tell where somebody is from based on physical appearance alone due to a considerable amount of migration. Culture and accent differ from region to region.
In the north of Middenfall, humans are more robust and stoic, owing to the colder temperatures. Many can trace their ancestry back to the nomadic people of Thorne. Clothing made from animal hides, and long thick hair or beards are common.
The south of Middenfall is one of the longest-settled human regions in Tide, here people often come from long lines of farmers. A large portion of Theder's nobility call Middenfall home, their ancestors making their money through land-ownership.
Humans in Twindrake are often sea-faring, and the most diverse in appearance with olive to dark skin and countless tales of the south seas and far-away lands. Due to the many ports and trade hubs in Twindrake, the people from here maintain the best relationships with other countries.
Westide is one of the most recently populated human regions on Tide and as such the people here still have a strong frontier spirit. More recent military expansion and a sense of opportunity can give these people an optimistic (and sometimes arrogant) air.
Humans in Pauviel and Lagatpulgoruz have adopted many of the cultural and personality traits of the elves or orcs that they live alongside.
It should be fine to play a human on this continent.
Vatan
In Vatan humans share a lot of their culture with the dragonborn who make up the majority of the population, including traditional dress and unique weapons such as the katana. They also equal the dragonborn in number.
It should be fine to play a human on this continent.