Often when I see "de facto" written somewhere it is in italic. For example:
LaTeX is a high-quality typesetting system; it includes features
designed for the production of technical and scientific documentation.
LaTeX is the >>> de facto <<< standard for the communication and publication
of scientific documents. LaTeX is available as free software.
Continued practices of expecting African Americans to ride in the back
of buses or to step aside onto the street if not enough room was
present for a Caucasian person and "separate but equal" facilities are
instances of >>> de facto <<< segregation.
Why?
Best Answer
It's a phrase imported from Latin (dē factō). Foreign phrases are usually written in italics.
Have a look at these two lists (1, 2). One sees them almost always in italics..