A block quotation refers to a longer quote that is set off from the rest of the text in a document with a greater indentation, smaller font size, or both. This is generally found in academic papers, though it may be found in any type of professional document. Different style guides for writing may all have different rules for the quote size that will require a block quotation. Generally, it is either based on word count, such as a quote of more than 50 words, or of text length, such as a quote that takes up more than eight lines in the text.
The idea of a block quotation is to make it easier for the reader to identify when the author of the paper is not speaking, but is quoting another source. Short quotes within the text are simply just set off with quotation marks on each side, which are easy enough to follow. Longer quotes with multiple sentences, however, can be more challenging to follow in the text, which is where a block quotation can come in handy. For academic papers, it also helps to indicate to the instructor how much of the paper is the student's own work, and how much is quoted.
A block quotation generally looks just like a literal block of text. It is typically not set off by quotation marks, and though it technically starts a new paragraph, the first line is generally not indented. Rather, the whole quote is set to the same indent mark. For instance, if the rest of the paper is set at one indent, a block quote might be set at two indents. It might be helpful to search for an example to see how this is done in the paper.
The spacing will usually remain the same throughout the quotation, based on the rest of the paper. For instance, if the rest of the paper is single spaced, then the block quote should also be. In most cases, the font will also not change, but for particularly long quotes, some style guides might recommend making the font smaller. Any questions about these issues or others when writing a paper should be directed to an instructor or looked up in the style guide that is being used, which is often very specific.