Asked by Ronyae ^(4,476)
Ronyae 39 days 21 hours ago. (More question by this person)

What is the proper use for "[ ]" in a sentence?

Answer from Lisa Lines ⁽²⁸⁰⁾
Lisa Lines 39 days 19 hours ago. More questions answered by this person)
Once use of square brackets is if you need to put something in brackets inside a bracket. For example, if you were writing an essay at university at you were inserting an in-text reference (for example those used in the Harvard method of referencing), and you wanted to also insert an abbreviation into that reference, it might look like this:

(Australian Bureau of Statistics [ABS], 2009, p. 88)

Another use is if you wish to insert something into a direct quotation that you are using in your essay. For example, if you wanted to note that you had added the italics to the quotations yourself for emphasis, or if you wanted to use 'sic' to point out that a mistake appeared in the original quotation. For example:

'It has been estimated that the official number historians cite for casualties in the Spanish Civil War is too low [emphasis added].' (I couldn't put the words in italics in this answer, but assume that 'too low' was in italics!)

or

'It has been estimated that the oficial [sic] number historians cite for casualties in the Spanish Civil War is too low.'

Hope that answers your question!

Answer from Connor Davidson ^(5,541)
Connor Davidson 39 days 10 hours ago. More questions answered by this person)
Most often I use them when quoting small bits of information with certain details missed out. For example: "He [Bob] went for a walk"

Answer from Darvin J. Hooey ⁽⁸⁰⁾ 39 days 2 hours ago. More questions answered by this person)
   Selected as Best Answer!   
They enclose additional editorial or clarifying information that has been added to a quoted statement that was not a part of the original quote.

"Billie Jean is not [Michael's] lover. She's just a girl who says that [Michael] is the one, but the kid is not [Michael's] son!"

Comment from Gregory Lewis ^(1,502) 38 days 3 hours ago.
Just additional information to Darvin's, you might include an article or short story in your anthology, magazine or journal. But you, the editor, want to explain or add something to the author's story or article. So, you use the square brackets as if to say, [This is your editor speaking. The author of this story you are reading probably didn't mean to write "bur," but "fur" - Editor]

Here's a real-life use, from Blake's The Book of Thel:

"The daughters of Mne [probably meant "Bne" - Ed.] Seraphim led round their sunny flocks,"

- G

Comment from Ronyae ^(4,476) 37 days 19 hours ago.
Thanks