How to make a Vaadin application Disability Friendlt

I develop applications that are consumed by diverse end users; a big number of whom have one form of disability or another.

Most of the Accessibility softwares parse html but in my case Vaadin doesn’t generate the traditional html that we are used to(html->head->body->html)

How can I make my applications disability friendly and accessible for screen readers on both web and mobile devices.

Thank you in advance.