Horizontal space

For a single spaced in text mode use the space bar for other spaces we have the following commands: \quad \qquad \hspace{...}  The command \hspace{...} (and \quad\qquad also available in math mode) supports the following units of measurement (positive and negative):
ptpoint(1 in = 72.27 pt)pcpica(1 pc = 12 pt)
ininch(1 in = 25.4 mm)bpbig point(1 in = 72 bp)
cmcentimetre(1 cm = 10 mm)mmmillimetre
dddidot point(1157 dd = 1238 pt)spscaled point(65536 sp = 1 pt)
In math mode we have the following commands:
\,a small space\:a medium space\;a large space\!a negative space (moves things back to the left)