White space
white space is any character or series of characters that represent horizontal or vertical space in typography. When rendered, a white space character does not correspond to a visible mark, but typically does occupy an area on a page. For example, the common white space symbol U+0020 SPACE (also ASCII 32) represents a blank space punctuation character in text, used as a word divider in Western scripts.
With many keyboard layouts, a white space character may be entered by pressing spacebar. Horizontal white space may also be entered on many keyboards with the Tab ↹ key, although the length of the space may vary.
TLDR: non visible character got by pressing spacebar for one or tab for multiple.
