overleaf table use enter inside cell code example
Example: latex newline in array cell
\begin{tabular}{|l|l|}
\hline
one line & \shortstack{two\\ lines} \\
\hline
XX & YYY \\
\hline
\end{tabular}
\begin{tabular}{|l|l|}
\hline
one line & \shortstack{two\\ lines} \\
\hline
XX & YYY \\
\hline
\end{tabular}