A Tikz solution:

The border is a separate picture, going into the footer, so appears on every page.
MWE
\documentclass{article}
\usepackage{graphicx}
\usepackage[margin=1in]{geometry}
\usepackage{fontspec}
\setmainfont{Noto Serif}
\usepackage{tikz}
\usetikzlibrary {positioning}
\newcommand{\gborder}{\tikz[remember picture,overlay]
\draw [black, line width=0.8mm]
([xshift=2em,yshift=2em]current page.south west)
rectangle
([xshift=-2em,yshift=-2em]current page.north east)
;}
\usepackage{fancyhdr}
\fancyhf{}% Clear header/footer
\renewcommand{\headrulewidth}{0pt}% Remove header rule
\fancyfoot[R]{\gborder\thepage}
\begin{document}
\pagestyle{fancy}
\begin{tikzpicture}[remember picture,overlay]
\node (uniname) at ([yshift={\dimexpr0.5\paperheight-8em}]current page.center) { \large Univerzitet u Nišu};
\node [below=of uniname,yshift=2em] (facname) {\large Filozofski fakultet};
\node [below=of facname,yshift=2em] (deptname) {\large Departman za psihologiju};
\node (cenpage) at (current page.center) {};
\node [above=of cenpage] (image) at (current page.center) {\includegraphics[height=7\baselineskip]{example-image}};
\node [below=of cenpage] (title) {\textbf{\Huge Anamneza}};
\node [below=of title] (subtitle) {\Large Psihopatologija posebni deo};
\node [below=of subtitle,xshift={\dimexpr-0.5\paperwidth+12em},yshift=-5em] (mentor) {\large Mentor: Nikola Ćirović};
\node [below=of subtitle,xshift={\dimexpr0.5\paperwidth-12em},yshift=-5em] (mentor) {\large Student: Danica Lezić, 2256};
\node (dateline) at ([yshift={\dimexpr-0.5\paperheight+8em}]current page.center) {Avgust, 2021, godine};
\end{tikzpicture}
\newpage
x
\newpage
x
\end{document}
\documentclassand ending by\end{document}) showing what you have already tried, So that we can copy paste to start with a compilable document which at least contains the text ! – Jhor Jan 21 '22 at 11:59