\documentclass[a4paper]{article}

\usepackage{graphicx}
\usepackage[grid]{eso-pic}

\AddToShipoutPicture{
  \begingroup
    \AtPageCenter{
      \circle{3}
    }
    \AtPageUpperLeft{
      \circle{3}
    }
  \endgroup
}

\begin{document}
~ % forced space as content, else latex won't produce output
\end{document}