Normally that doesn’t happen: long lines of text should wrap automatically, as you can see at the SAC Demo. For example, try entering this long text to see how it works:
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Praesent pharetra libero a nunc vehicula faucibus. In hac habitasse platea dictumst. Duis posuere augue ex, rutrum aliquam sem commodo nec. Vivamus ac dui est. Vivamus vestibulum lorem massa, at maximus turpis consectetur in. Aenean tincidunt enim urna, eu accumsan nisl euismod eu. Sed vitae auctor tellus.
So if the auto-wrapping is not happening in your case, it could be that your theme (or maybe a plugin or something) is overriding the default CSS styles. If you have a URL where I can see the form, I would be glad to take a look.