\documentclass{article}
\usepackage{tikz}
\usepackage[utf8]{inputenc}
\usepackage[english,greek]{babel}
\begin{document}
vlepe eikona ~\ref{fig:1}
\begin{figure}
\centering
\begin{tikzpicture}
\draw[step=0.5cm,gray,very thin] (-2,-1) grid (2,4);
\draw[->] (-2.2,0) -- (2.2,0) node[right] {$x$};
\draw[->] (0,-1) -- (0,4.2) node[left] {$y$};
\foreach \x in { -2,-1,2,1}
	\draw (\x,0) -- (\x,-0.1) node[below] {\x};
\foreach \y in {1,2,3,4}
	\draw (0,\y) -- (-0.1,\y) node[left] {\y};
 \draw[scale=1 , domain=-2:2 , smooth , variable=\x, blue, thick]
 	plot({\x} , {pow(\x , 2)}) node[right] {$y=x^2$};
\end{tikzpicture}
\caption{synarthsh $y=x^{2}$}\label{fig1}
\end{figure}
\end{document}

