I will add to the @share2steem answer that customization options are also now available so you can choose how your post will appear on Steem. I would suggest you go on the website https://share2steem.com and click on the Social Networks tab.

You should see the account you linked.
Click on the name of the account and look around on the page :
You should see instructions on how to customize your title and the body of your post (Steem-side), and at the end (for Twitter accounts) you will see an option to cross-post everything (except retweets and replies) without the need to add the hashtag #share2steem in your tweet.

Thanks a lot for your interest. We try to constantly improve and your feedback is greatly appreciated !