Space | Difference between \vspace and \vspace*

For deleting white spaces, without the * the skip is always discarded at the start of the page (whitin the page frame), and with the * it is discarded within the page header.

Summary:

\vspace{-2cm}: Discards white space within the page frame. 

\vspace*{-2cm}: Discards within the page header.

%————-

“So \newpage\vspace{-2cm}Hello will print Hello inside the page frame, whereas\newpage\vspace*{-2cm}Hello will print it somewhere probably inside the page header? That’s the idea yes.”

Source: tex.stackexchange.com