As far as I can tell, he did not instruct Twitter employees to make his Tweets appear to all users, but he did want them to make his posts appear in timelines significantly more often. This lead to reports of users suddenly getting their timelines flooded with lots of his Tweets.
It seems like there was a rush within Twitter to raise Musk’s engagement numbers by altering the recommendation algorithm to specifically boost posts from his accounts. The special boost factor was later reduced, but allegedly still exists.
[0] https://www.theverge.com/2023/2/14/23600358/elon-musk-tweets...