Textual Elements in Notebooks
Mathematica's unified symbolic document architecture makes it possible to have flowing text contain any kind of object—including math, graphics or dynamic elements.
"string" a string containing arbitrary ordinary or special characters
Row — show a list as a row of abutting elements, potentially extending over several lines
Spacer — a spacer of specified size
Invisible — space the same size as a given expression
Riffle — intersperse elements into a list
Text — use text fonts and other text formatting for an object
Style — specify arbitrary styles for an object
TextCell — create a complete text cell, with any cell options
StringForm — display with expressions interleaved with a raw string
Alt+7 — interactively create a new text cell in a notebook
Ctrl+( — start an inline text cell inside any expression
