You have a choice between indenting the first line of paragraphs (often used in student papers, books, and magazine articles) or using unindented (block) paragraphs (as in business memos and reports). If you do not indent first lines, then you should use a space break between paragraphs.
Text with a first-line paragraph indent is typical for extended text like an academic paper.
Text with a hanging indent can be useful for technical documentation, newsletter or résumé design, or a bibliography.
A block indent is used in academic papers to set off long quotations.
Paragraph indent in an academic paper
Hanging indents in academic papers (MLA and APA)
Block indents in academic papers (MLA and APA)