##  Class files

LaTeX will automatically indent the first line of each paragraph that doesn't immediately follow a section heading. If you'd like to get rid of an indent, you can use the \noident command: \section{Introduction} This is the first paragraph.   \noindent This is the second paragraph. If you'd like to indent the first paragraph after a section tag, you can include the indentfirst package in your preamble: \usepackage{indentfirst} If you'd like to indent a whole paragraph, there are several techniques described in this post on the TeX StackExchange forum.