Forms must have labels. Visually impaired users must rely on screen readers to read the text in your forms, but this assistive technology requires labels in order to provide accurate context.
If your form is not using the CMS' Form Builder and KaratEmail already, converting your form into one of those is the easiest way to make the form accessible and sustainable to those who will need to edit the form after you.
To get access to the Form Builder in the CMS, if you have not done so already, is to take our Web Forms training module, CMS 130. This should take you about an hour.
If you need more information on how to make your non-CMS form accessible, check out WebAIM's article on creating accessible forms.