The environmental campaign was well-publicized on all major social media platforms.

well-publicized 是由副词 well（好地）和动词 publicize（宣传、公布）的过去分词 publicized 组成的复合形容词。publicize 由名词 public（公众）加上动词后缀 -ize 构成，意思是"使公开、宣传"。 well-publicized 表示"被广泛宣传的、被大量报道的"，强调宣传活动做得很好，覆盖面广。