In order to copy the link to get credit for a shared Twitter post, you must add a comment and not simply retweet the post. This is done by clicking the retweet icon, and then typing a comment in the “Add a comment…” box. Once you are done, click Retweet and go to your profile. Find the tweet and click on the upside-down carrot (^) for the menu options. Click on “Copy link to Tweet.” Notice that this link will take you to a page dedicated to your specific retweet, and not the original tweet that you are reposting. If you simply retweet a post without a comment and click “Copy link to Tweet,” it will link back to the original, and you will not receive credit for your share.
Note: you will NOT be credited for retweets if your account is private. Your posts must be public.