\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{hyperref}
\usepackage[margin=1in]{geometry} % full-width
\topskip = 20pt
\parskip = 10pt
\parindent = 0 pt
\baselineskip = 15pt
\usepackage{pdflscape}
\usepackage{amssymb, amsfonts, amsmath}
\usepackage{bm}
\usepackage{booktabs}
\usepackage{setspace} % line spacing
\onehalfspacing
\usepackage{graphicx}
\usepackage{adjustbox}
\usepackage{rotating} % for sidewaystable
\usepackage{threeparttable}
\usepackage{dcolumn} % aligning decimals
\newcolumntype{d}[1]{D{.}{.}{#1}}
\let\estinput=\input % define a new input command so that we can still flatten the document
\newcommand{\estauto}[3]{
\vspace{.75ex}{
%\textsymbols% Note the added command here
\begin{tabular}{l*{#2}{#3}}
\toprule
\estinput{#1}
\bottomrule
\addlinespace[.75ex]
\end{tabular}
}
}
\newcommand{\sym}[1]{\rlap{#1}}
\usepackage{hyperref}
\usepackage{tabulary}
\title{Project Name}
\author{X Y Z}
\date{September 2021}
\begin{document}
\maketitle
\section*{Summary Statistics (Tables)}
\subsection*{Consent}
\begin{table}[!htbp]
\centering
\caption{caption}
\label{tab:meetattend}
\estauto{xyz.tex}{8}{c}\\
\small{\textit{Notes:}}
\end{table}
\end{document}
I apologise for my earlier post. I am very new to the forum and latex and posting for the first time. I have a file named xyz.tex in the project which looks like this:
&\multicolumn{8}{c}{var name} \\
& N& Mean& SD& Min& 10th p.& Median& 90th p.& Max\\
\midrule
x & a& b& c& 0& 1& 1& 1& 1\\
y & 120& 0.825& 0.382& 0& 0& 1& 1& 1\\
z & 243& 0.778& 0.417& 0& 0& 1& 1& 1\\
I get an error while compiling the pdf on overlead but when I remove \usepackage{booktabs}, the pdf is rendered but the table has no lines etc. I am not sure how to paste the error. I am not sure why that is happening. Any help is appreciated.

\inputinside the table with\bottomrulefollowing right after it. It's the same problem in this question here. Try the code suggested by the accepted answer and see if it fixes it. – frabjous May 10 '22 at 00:59