\documentclass[a4paper, 12pt]{report}
\usepackage{anyfontsize, times, siunitx, ragged2e, setspace, titlesec}
\usepackage{enumitem}
\usepackage{lscape, tabularx, booktabs}
\usepackage{rotating}
\setlength{\parindent } { 10ex }
\doublespacing
%\titleformat{command}[shape]{format}{label}{sep}{before-code}[after-code]
\titleformat{\chapter}[display]{\normalfont\bfseries}{\huge Chapter \thechapter}{2pt}{\Large\bfseries}
\titlespacing{\chapter}{ 0cm }{-3cm }{0.5cm}
\begin{document}
\chapter{Summary}
Buffaloes contribute significantly to dairy economy by being the major milk producers in Indian subcontinent. Genetic progress in buffalo has been slow as compared to cattle due to low adoption of AI. \section{AI} Poor post thaw semen quality has contributed to poor AI conception rates in buffalo. Buffalo spermatozoa are more sensitive to freezing as compared to cattle spermatozoa due to a different sperm lipids ratio.
\subsection{Normality }Application of sub optimum semen freezing protocols standardized in cattle are being used for buffalo cryopreservation . Evaluation of freezing rates for buffalo spermatozoa, reveal finer controls on damage through manipulation of cooling rates at critical temperature zones of freezing
\paragraph{Cost}
Cryopreservation results in temporary, as well, as permanent loss of vitality and viability in more than 50 percent of total sperm, leading to loss of resources. Increasing cost of production and semen sexing has resulted in decrease in number of spermatozoa per insemination dose and subdued economic targets of a breeding bull semen collection
\end{document}
我希望文本在下一行开始缩进\paragraph，减少\section和文本开始之间的垂直空间。
答案1
要使段落标题具有block样式：
\titleformat{\paragraph}[block]
{\bfseries}
{\theparagraph}
{}
{}
要减少章节标题后的垂直空间（此处设置为0.5ex）：
\titlespacing{\section}{0pt}{2ex}{0.5ex}
缩进第一行每一个切片命令：
\usepackage{indentfirst}