The marks palette contains various accents, marks, negations, slashes, and enclosures that can be applied to a single symbol. For stretchable marks that can be applied to larger expressions, use the wide marks palette.
When a mark is selected from this palette, it is applied to the character immediately preceding the caret in the equation, or if there a character is selected, then it is applied to the selected character. If multiple characters are selected, then the mark is applied to the last character in the selection.
In this palette, rows 3 and 4 are identical to rows 1 and 2 but with marks below the character instead of above.