Here "word" is a metonym for "a message." This means that he sent a messenger to Joab with a request. Alternate translation: "Absalom sent a messenger to Joab asking him" (See: [[rc://en/ta/man/translate/figs-metonymy]])
It is implied that Absalom wanted Joab to come to him to see him and to intercede for him so that he would be allowed to see the king. The full meaning of this can be made clear. Alternate translation: "to come to him and to intercede for him so that he could see the king" (See: [[rc://en/ta/man/translate/figs-explicit]])
Here "word" is a metonym for "a message." This means that he sent a messenger to Joab again with the same request. The full meaning of this can be made clear. Alternate translation: "So Absalom sent a messenger to Joab again with the same request" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-explicit]])