How to change link of an uploaded file to the media library

If you are talking about menus and your theme uses the Menu API, then upload the PDF to a publicly accessible server– doesn’t have to to be the one your site uses– then

 go to Appearance -> Menus,
 Navigate to a menu, or create one
 find the "Links" dialogue,
 input the URL and the link text
 Save

Thank you

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)