documentclass[a4paper,12pt]{article}
%twoside yaz iki taraflı için
usepackage[top=2.5 cm, bottom=2.5 cm, left=4 cm, right=2.5 cm]{geometry}
usepackage[turkish,shorthands=:!]{babel}
usepackage[backend=biber,style=numeric, sorting=none]{biblatex}
usepackage{titlesec}
titlespacing{section}{0pt}{8 cm}{40pt}
usepackage{fontspec}
setmainfont{Times New Roman}
begin{document}
section{hi}
Latex is the best
subsection{how are you?}
But sometimes it's hard
end{document}

titlespacing{section}{0pt}{8 cm}{40pt}