How can I add these information at the titlepage?

Question

How can I add the name of university and the name of supervisor at the title page of my thesis?

Do I have to add a command before or after \maketitle?

\begin{document} 

\title{ Blabla } 

\author{ Blabla } 

\date{ } 

\maketitle

EDIT:

I wrote the following:

\begin{document} 

\begin{titlepage}
\begin{center}

\HRule \\[2cm] % Horizontal line
{\huge \bfseries BLaBLa}\\[0.4cm] % Thesis title
\HRule \\[3cm] % Horizontal line

\begin{minipage}{0.4\textwidth} 
\begin{center}
 \Large{Name} 
\end{center}
\end{minipage}\\[2cm] 


\begin{minipage}{0.4\textwidth} 
\begin{center}
\Large
\emph{Επιβλέπων καθηγητής:} 
{name}
\end{center}
\end{minipage}\\[2cm]

\textsc{\Large Μεταπτυχιακή εργιασία}\\[2cm] % Thesis type 

\textsc{\LARGE blabla}\\[0.4cm] 
\textsc{\LARGE University}\\[2cm] % University name

{\large \today}\\[4cm] 

\vfill
\end{center}

\end{titlepage}
\end{document} 

but I get the following error for the line

\HRule \\[2cm] % Horizontal line
{\huge \bfseries BLaBLa}\\[0.4cm] % Thesis title
\HRule \\[3cm] % Horizontal line 

What does this mean?

Answer 1

You can define a new command \HRule to print a horizontal rule with

\newcommand*{\HRule}{\hrule height 5pt}

You can change the numer after height to get a lower or higher rule.

Your command for a new line with special space to the next line \\[2cm] does then not work. Instead use the command \vspace{2cm}.

With that changes your code compiles with:

\documentclass[chapterprefix=true]{scrreprt}

\newcommand*{\HRule}{\hrule height 5pt} % <===========================


\begin{document} 

\begin{titlepage}
\begin{center}

\HRule  % <===========================
\vspace{2cm} % <===========================
{\huge \bfseries BLaBLa}\\[0.4cm] % Thesis title
\HRule  % <===========================
\vspace{3cm} % <===========================

\begin{minipage}{0.4\textwidth} 
\begin{center}
 \Large{Name} 
\end{center}
\end{minipage}\\[2cm] 


\begin{minipage}{0.4\textwidth} 
\begin{center}
\Large
\emph{Επιβλέπων καθηγητής:} 
{name}
\end{center}
\end{minipage}\\[2cm]

\textsc{\Large Μεταπτυχιακή εργιασία}\\[2cm] % Thesis type 

\textsc{\LARGE blabla}\\[0.4cm] 
\textsc{\LARGE University}\\[2cm] % University name

{\large \today}\\[4cm] 

\vfill
\end{center}

\end{titlepage}
\end{document} 

and the result:

You asked in a comment for the documentation: If you have a TeX distribution installed on your computer, you can use texdoc koma-script or---if you use a online compiler---search the internet for file scrguide.pdf (German version) or scrguien.pdf (English version) or you can try texdoc.net, but the versions are not always up-to-date.