He called to his friends VS He called his friends

Hi,

One boy was very near the cab. He called to his friends. But shouldn’t it be “… He called his friends”? Why do that “to”?

Thanks. See you soon.

He didn’t call them. He called to them.
There is a difference.

‘He called his friends’ indicates that he called them and they possibly came over.
He called to his friends’ indicates that he used a loud voice to speak to them, so that they could hear him over the distance, but there was no intention of them approaching.