documentclass[a4paper,twocolumn]{article}
usepackage[margin=1in]{geometry}
usepackage{multirow,booktabs}
setlengthparindent{0pt}
begin{document}

begin{tabular}{|c|c|c|c|}
hline
multirow{2}{*}{USERNAME} & multirow{2}{*}{PASSWORD} & Did the user denied access to the app when the user inputted wrong username or password? \

                         &                          &  YES                    & NO \
                    hline
papad@gmail.com          & 7221456                  &                         & \
                     hline
idislikeyou@gmail.com    & password                 &                         &  \
                     hline
devs@gmail.com           & 12A2ZAQR                 &                         & \
                     hline
devs@gmail.com           & password                 &                         & \
                     hline

end{tabular}

end{document}

documentclass[a4paper,twocolumn]{article}
usepackage[margin=1in]{geometry}
usepackage{multirow,booktabs}
usepackage{amssymb}
usepackage{array}

newcolumntype{C}[1]{>{centeringarraybackslash}p{#1}}
setlengthparindent{0pt}
begin{document}

    begin{center}
        begin{tabular}{@{}*{2}{c}*{2}{C{.5linewidth}}@{}}
        toprule
        multirow{2}{*}{USERNAME} & multirow{2}{*}{PASSWORD} & multicolumn{2}{C{linewidth}}{Did the user denied access to the app when the user inputted wrong username or password?} \ cmidrule{3-4}
                                  &                           &    YES     &                                                      NO                                                       \ midrule
             papad@gmail.com      &          7221456          & checkmark &                                                                                                               \
          idislikeyou@gmail.com   &         password          & checkmark &                                                  checkmark                                                   \
             devs@gmail.com       &         12A2ZAQR          & checkmark &                                                                                                               \
             devs@gmail.com       &         password          &            &                                                  checkmark                                                   \ bottomrule
    end{tabular}
    end{center}

end{document}