Form with different subjects

I have a contact form that allows users to send mails with different email addresses according to their type of there query.
Now I want you to each type of request (and e-mail) corresponds its own subject.

Example:
Topic: General Questions -> send by Mail: [email protected] -> I receive the mail with the Subject: “General inquiry from your website”
Another Topic: Sale of product -> send by Mail: [email protected] -> I receive the mail with the Subject: “Search by product purchase”

What I need is that the mails are sent to my email with a different Subject, according to the type of query.

Thanks!