Reposting -- or retweeting -- on Twitter allows you to instantly share another user's tweet with your followers. You can use the built-in retweet feature to share someone else's tweet with all of your followers. You can also manually retweet an existing tweet, adding "RT" or "MT" to signify that you are reposting someone else's content.
Whether you use a PC or Twitter's mobile app, below every tweet is a retweet icon that you can click to repost the tweet. The retweet icon is located next to the reply arrow and looks like two vertically stacked arrows. If you are using a PC, click the retweet icon and Twitter will then ask if you want to retweet this tweet to your followers. Click Retweet. Twitter now posts the tweet to your profile and your followers' timelines accompanied by the retweet icon and a note that you retweeted it. If you change your mind you can undo the retweet by again clicking the retweet icon.
You can also repost tweets on your mobile device's Twitter app. Tap the retweet icon as you would on your PC. Twitter now asks whether you want to retweet the tweet or if you want to quote it. Tap "Retweet" and Twitter automatically reposts the tweet just as on your PC.
Another way to repost a user's tweet is to manually copy and paste an entire existing tweet. If you are on a PC, copy the tweet from your timeline, or you click on the tweet to view the details and copy it from there. If you are using the mobile app, tap the Tweet in your timeline and view the details. Copy the tweet, then return to your timeline or profile. Now tap the tweet icon to compose a new tweet. Paste the text you've copied and add "RT" and the original tweeter's Twitter handle to the beginning of your post to show this isn't your content. Click or tap Tweet and Twitter posts the tweet to your profile and your followers' timelines.
You can also modify and repost another user's tweet. Manually modified tweets are designated by "MT" and are usually shortened so a user can include his own comments. To modify and repost a tweet on your PC, copy the tweet as if to manually retweet it. Now paste the tweet, delete parts and add your own observations. Leave enough space to include "MT" and the original tweeter's Twitter handle. If you are using the mobile app, you can use the Quote Tweet feature. Tap the retweet icon and then tap Quote Tweet. Twitter provides the full tweet in quotation marks. Add "MT" and the original tweeter's handle at the beginning to signify that you are quoting another user's tweet, or add "via" and the user's Twitter handle to the end.
To view your tweets that have been retweeted by others, go to the Notifications Section. You can view all activity concerning your Tweets, including which have recently been retweeted and by whom. However, you won't see manual retweets and modified tweets here. When you manually repost a tweet, the original tweeter does not get the "favorites" or retweets, even though you've added "RT" or "MT" and the user's handle. Some users dislike manual retweets and modified tweets because the resulting favorites or retweets improve the reposter's own statistics and credibility, not the original tweeter's.