\documentclass[a4paper,twoside,fontsize=12pt,appendixprefix=true]{scrreprt}

\addtokomafont{captionlabel}{\bfseries}
\usepackage{lmodern}
\usepackage[a4paper]{geometry}
\geometry{a4paper}
\usepackage{fancyhdr}
\usepackage[onehalfspacing]{setspace}

\usepackage{pdfpages}
\usepackage{epsfig}

%\usepackage{floatpag}
%\floatpagestyle{empty}

\usepackage{color}

\usepackage{graphicx}
\setcapindent{0em}

\usepackage{tikz}
\usepackage{tikz-3dplot}

\usepackage{amsmath}
\usepackage{amssymb}

\usepackage{textcomp}

\usepackage{threeparttable}
\usepackage{longtable}
\usepackage{tablefootnote}
\usepackage{multirow}
\usepackage{multicol}
\usepackage{colortbl}
\usepackage{caption}

\usepackage{booktabs}

\usepackage[ngerman]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

%\usepackage{natbib}

\usepackage{siunitx}

%\usepackage{hyperref}
\usepackage[hidelinks]{hyperref}

\fancypagestyle{mainpart}{
	\fancyhf{}
	\lhead[\leftmark]{}
	\rhead[]{\rightmark}
	\lfoot[\thepage]{}
	\rfoot[]{\thepage}
}
\setlength{\parindent}{0pt}
\renewcaptionname{ngerman}{\figurename}{Abb.}