It looks like an "x" but not quite. I am using Adobe Illustrator 2023 on a Mac, if that matters.
If you don't know how to use Glyphs panel, the quicker way is to google "multiplication sign" and you will get this character "×".
Copy paste this character "×" into your document and, assuming your font includes this character (some fonts can have a limited math symbols set), then you should be good to go.
Provided the symbol is included in the font you're using, all of its symbols can be found in the Glyphs palette.
- Make sure you have a blinking text cursor by creating or editing a text with the Text tool;
- Open the Glyphs palette through Type > Glyphs;
- Scroll through the available glyphs in the palette and find the multiplication symbol;
- Double-click the symbol.
This will output the symbol you chose on the position of your text cursor.