\documentclass[11pt]{report}
\usepackage{titlesec}
\usepackage
[
        a4paper,
        left=2cm,
        right=2cm,
        top=3cm,
        bottom=4cm,
]
{geometry}



\titleformat{\chapter}[display]
  {\Huge\bfseries}
  {}
  {0pt}
  {\thechapter.\ }
  
\titleformat{name=\chapter,numberless}[display]
  {\Huge\bfseries}
  {}
  {0pt}
  {}
  
\pagenumbering{arabic}

