documentclass[letter,landscape]{report}

newcommand{ReportTitle} {Summary Report }
newcommand{ReportAuthor}{Mister San }

pdfinfo{
    /Title   (ReportTitle)
    /Author  (ReportAuthor)
    /Subject (Generated by ReportAuthor on today)
}

begin{document}
    ReportTitle \
    By: ReportAuthor \
end{document}

documentclass[letter,landscape]{report}

newcommand{ReportTitle} {@Model.ReportTitle }
newcommand{ReportAuthor}{@Model.ReportAuthor }

pdfinfo{
    /Title   (ReportTitle)
    /Author  (ReportAuthor)
    /Subject (Generated by ReportAuthor on today)
}

begin{document}
    ReportTitle \
    By: ReportAuthor \
end{document}

newcommand{ReportTitle} {Standard_Report }

newcommand{ReportTitle} {# $ % & ~ _ ^ { } backslash}

./main.tex:7: TeX capacity exceeded, sorry [input stack size=5000].
@inmathwarn ...latex@warning {Command protect #1
invalid in math mode}fi l.7        /Title   (ReportTitle)