Yes! You have the ability to save an invoice as a "draft" which will allow you to preview all of the information that you have included in the invoice before sending it out. To save an invoice as a draft simply hit the "Save as Draft" button next to the "Send button when creating your invoice on your Square Dashboard. 

If you have never sent an invoice before and want to see what the final product looks like, I would highly recommend sending your self a test invoice for a dollar so you can make sure everything looks just the way you want it too!