How do I adjust size of title column in check box field?

If I understand correctly, you want to adjust the size of the title/label of the checkbox field on your form? It appears that the label you are currently using for your checkbox is a Text Field. Since it is a text field, we can easily adjust the size of the title by changing the font size of the text.

If you are referring to a different concern, please let us know so we may better assist you.
Regards.