Is there a way to assign an html ID automatically to a field in a content type?
Since I was only displaying the content with a view, in the view settings
- I edited the specific field  
- clicked REWRITE RESULTS 
- checked "Rewrite the the output of this field" 
- and wrote:

&lt;p id="file-types"&gt; [field_file_type_text] &lt;/p&gt;

This solved the problem