To ensure that quotation marks are properly typeset, it is important to use the correct PreTeXt code. To set something off in double quotes, use the <q> tag around what should appear in quotes. It will supply both the opening and closing quotation marks, as in: “This is a quotation.” If you need single quotes, use <sq>. Because the content of <q> and <sq> is quite restricted, you may find yourself needing to explicitly access the left and right single and double quotation marks. They are, quite sensibly, <lq>, <rq>, <lsq>, and <rsq>.
Longer quotes are best set off using <blockquote>