CATIA V5 has two levels of describing dimension appearance; a Standard and a Numerical Display Description. You can define as many of these as you want, as long as you have admin privileges.
The drafting Standard defines general drawing & dimensioning rules based on ASME, ANSI, ISO, DIN, JSI, etc. standards.
The dimension Description defines what the dimension actually looks like; inch, millimeter, feet-inch, MAX/MIN, smaller text size for tolerances, etc.