Is it prop must be named as render for render props?

Even though the pattern named render props, you don’t have to use a prop named render to use this pattern. i.e, Any prop that is a function that a component uses to know what to render is technically a “render prop”. Lets take an example with the children prop for render props,

<Mouse
  children={(mouse) => (
    <p>
      The mouse position is {mouse.x}, {mouse.y}
    </p>
  )}
/>

Actually children prop doesn’t need to be named in the list of “attributes” in JSX element. Instead, you can keep it directly inside element,

<Mouse>
  {(mouse) => (
    <p>
      The mouse position is {mouse.x}, {mouse.y}
    </p>
  )}
</Mouse>

While using this above technique(without any name), explicitly state that children should be a function in your propTypes.

Mouse.propTypes = {
  children: PropTypes.func.isRequired,
};