We use a contact form 7 for each product we sell at our website.
Like here :
Sometimes, people who use the contact form forget to put in the subject, they assume that the contact form is smart enough to fill it up for them when they submit.
Is there a way to pass a subject by default each time the page/post is accessed ? Then when they are filling it up to enquire, they don't have to worry about the subject. Then we can pass the relevant default subject to a contact form depending on the which page it is located.