Hi Prasunjeet,
In layout pages, renders the content of a named section.
RenderSection renders only a part of the child view which is wrapped under the named section.
Multiple RenderSection() methods are allowed in a single layout view.
The RenderSection() method includes boolean parameter required, which makes the section optional or mandatory. If the required parameter is true, then the child view must contain the section.
Refer below link for more details.
RenderSection Method
RenderSection With Example