Navan Inc. a business travel and expense management software maker, filed publicly for a US initial public offering.The Palo Alto, California-based company had a net loss of $99.9 million on revenue of $329.4 million for the six months ending July 31, compared with a net loss of $92.5 million on revenue of $253.7 million in the corresponding period a year earlier, according to its filing Friday with the US Securities and Exchange Commission....