Add/Remove Cell Tags opens a dialog box that allows you to add or remove cell tags associated with the selected cell(s).
Cell tags are used to find single cells or classes of cells. For example, all title cells could be given the tag Title, and all cells related to a particular subject could be given a cell tag identifying that subject.
To add a new cell tag to the selected cell or cells, type a word in the "Cell tag:" text box, then click Add. You can add or remove multiple cell tags at once. Separate multiple cell tags with commas.
Mathematica attaches the specified cell tag to each of the selected cells. The cell tags are not visible unless Show Cell Tags in the Find menu is checked.
All cell tags defined in a particular notebook are visible in the Cell Tags submenu under the Find menu. To search for cells according to their cell tags, you can use either the Cell Tags submenu or the Find in Cell Tags command .