When a client looks at my Goals Form, they only see checkboxes under each questions, instead of fields to type. Why is that?

That happened when you choose "List" for the type of answer you'd like to be available for your clients when answering the question. The way the "List" option works is not so much to provide the client with 3 text boxes to list their top 3 goals (each in their own box), but rather to give your client a list of items to choose from.  So, when you choose "List" as the answer type, you would then actually type in the items you want displayed in the list and then your client could choose one, some or all of the items on the list to answer the question.

The only form that allows you to insert multiple text boxes for your clients to organize their answers in would be the Goals form. That might be where you want to post your question about "What are your top 3 goals?" and then you can choose within the Goals form that you want 3 text answer fields for that question.