When we say “white”, it refers to pure, no impurity or bad things, similarly white hat SEO means no illegal or bad means of achieving top rankings. It is pure and totally legal ways, without spamming and stuffing of keywords.
White Hat SEO refers to the use of SEO strategies, techniques and tactics that focus on human audiences, as opposed to search engines and completely follow search engine rules and policies.
Any SEO tactic that maintains the integrity of your website and the SERPs (search engine results pages) is considered a "white-hat" search engine optimization tactic. These are the only tactics that we should use whenever applicable and which enhance rather than detract from your website and from the rankings.