Tweet text is generated automatically, depending on your settings for every click to tweet link or quote box that you create. You can change the URL to tweet or add any hidden text to the quote text, for example to add hashtags.
However you can use a custom tweet text, which does not have to follow the text inside a click to tweet box. This feature is extremely helpful, when the quote text is too long and you want to make it shorter for a tweet.
You can check how it works, if you click-to tweet the quote box below