Spacing between ArcMap class name and description in the legend

There are several ways to approach this..

Firstly, convert the legend to graphics, ungroup and move the text to fit (not recommended, if you change the symbology the graphics will not auto update).

Secondly, replicate the layer twice but leave the visibility turned off. Remove the layer you currently have from the legend, add both new layers then remove the symbol classes so that one has pasture to wheat and the other has barley to grazing mix.

Third, change the description of Canola - Roundup Ready to two lines, see https://support.esri.com/en/technical-article/000002680 for more info.

Fourth, change the legend properties to fix the width of the column text which will also break items into multiple lines automatically.

One way to do this is that you could add a new field with the "description (ac)" values, and then use the Field Calculator to concatenate your "crop type" and ac field values, with a space (or 2 or 3) between them into one that you perhaps call ConcatField.

You can then symbolize using ConcatField and that will carry the text you are after through to your legend.