@Shraddha Bathla wrote:
... and after completeing your selection you get to know that.
I am also not sure I understand your question. The Pen tool does not create a selection directly, but after you have drawn a Path you can convert the path to a selection.
If you mean that you have drawn a path with the Pen tool and the path is complete, there are tools to add and delete the anchor points. Right-click the Pen tool in the Tools panel to see the hidden tools > choose the Delete Anchor Point tool and click the anchor point to remove it.
To adjust points, use the Direct Selection tool "A" (white arrow).
If we are misunderstanding, share a screenshot. Use the Insert Image button (mountain and sun) in a Reply window.
Jane