Reducing the size a text box creates

Hello!
I have attached a screenshot of the top 1/3 of a document as an example below, but how can I go about reducing the amount of space that a text box creates in a document? It's not allowing me to move the text box - in this case - closer to the title of the exercise because I would like to cut down the length of the document and I think it just looks less professional with such a large gap.