Setting paragraph's first line indentation
Just like shifting an entire paragraph or document to the right, you can also shift only the first line in every paragraph.
This is useful for denoting the start of a new paragraph without necessarily modifying the line spacing or even paragraph spacing, for economy of room on each page. You can do this manually by simply hitting Tab after starting a new line, or you can set it up to indent automatically in the Paragraph menu.
Using this feature is recommended for reports, technical documents, academic papers - essentially any document of a moderate length that is going to be free of other media (pictures, etc.) and needs to be easy to read.
It is less important for web copy and articles that will be subject to a website’s individual formatting settings.