The last of the tweet icons which appear as 3 dots, is called the “More” icon, see above image. This will give you options you can apply to a tweet you view. If you wish to share that tweet with someone, block the tweet from another member, and do other functions as well, you can do that by clicking this icon. As you can see in the below image, there are 6 functions you can perform

That drop down menu of 6 options will only appear when clicked on a tweet that is not your own. If you were to click on the “More” icon that appears on your tweet, you would get another drop down menu, but in this one only 4 options are available, see below image.

Personally I do not use hardly any of these options. The only one I will use is the Delete option for a tweet I create that I want to delete because I made a mistake. So for the most part, the only icons I use are the “Retweet” and the “Favorite” icons.