Saving the currently displayed page
Pressing alt-t will download a PDF containing the currently displayed music in the VHV webpage. If the graphical music is wider than it is high, the downloaded PDF will be in landscape mode; otherwise, the PDF will be in portrait orientation.
Files will be downloaded wherever your browser saves downloaded files. Here is a demonstration of typing alt-t to save a file and then opening the downloaded PDF in another tab in the web browser.
Saving the entire score to a PDF file
Pressing alt-shift-T will download a PDF containing the entire score. The layout in VHV will not be used but rather the music will be typeset for letter-sized paper in portrait orientation: